Dunning

Customer statements: the open items of one customer on a day, tied to the receivables control account, as JSON, CSV or a PDF in the customer's language, archived with its hash when a person issues it. Vendor statements: the movements on a vendor's account between two days with the running balance. Reminder letters: which customers are due one, the letter in their language, archived, sent or recorded as handed over. No fee and no interest; nothing here posts.

Operation	Summary	Scope	Idempotency-Key
`GET /v1/documents/{document_id}/dunning-block`	Get whether the reminders of an invoice are stopped	`read`
`POST /v1/documents/{document_id}/dunning-block`	Stop the reminders of an invoice	`post`	required
`DELETE /v1/documents/{document_id}/dunning-block`	Resume the reminders of an invoice	`post`
`GET /v1/entities/{entity}/customers/{party}/activity`	Get a customer's activity statement: invoices, credit notes and payments	`read`
`POST /v1/entities/{entity}/customers/{party}/reminders`	Make a reminder letter to a customer	`post`	required
`GET /v1/entities/{entity}/customers/{party}/statement`	Get a customer's statement of account	`read`
`POST /v1/entities/{entity}/customers/{party}/statement/issue`	Issue a customer's statement: archive its PDF	`post`	required
`GET /v1/entities/{entity}/reminder-settings`	Get the fees and default interest of the reminder levels	`read`
`PUT /v1/entities/{entity}/reminder-settings`	Save the fees and default interest of the reminder levels	`admin`
`GET /v1/entities/{entity}/reminders`	List the reminder letters	`read`
`GET /v1/entities/{entity}/reminders/proposal`	List the customers due a reminder letter	`read`
`GET /v1/entities/{entity}/vendors/{party}/statement`	Get a vendor's statement: what we owe, by bill, credit note and payment	`read`
`GET /v1/reminders/{notice_id}`	Get a reminder letter	`read`
`POST /v1/reminders/{notice_id}/mark-sent`	Record that a reminder letter was handed over	`post`	required
`GET /v1/reminders/{notice_id}/pdf`	Download a reminder letter	`read`
`POST /v1/reminders/{notice_id}/send`	Send a reminder letter by e-mail	`post`	required
`POST /v1/reminders/{notice_id}/withdraw`	Withdraw a reminder letter not handed over	`post`	required

`GET /v1/documents/{document_id}/dunning-block`

Get whether the reminders of an invoice are stopped

The stop on the invoice's reminders, with who set it, when and why; block is null when reminders go out as usual.


Required scope	`read` (`admin` implies every scope)
Operation id	`get_dunning_block_v1_documents__document_id__dunning_block_get`

Parameters

In	Name	Type	Required	Description
path	`document_id`	string	yes	Document id (uuid) or number, e.g. `INV-2026-000001`.

Example request

curl "$ERP_URL/v1/documents/INV-2026-000001/dunning-block" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	OK	`DunningBlockState`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "block": {
    "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "number": "string",
    "reason": "string",
    "blocked_by": {},
    "blocked_at": "2026-09-21T09:30:00Z"
  }
}

`POST /v1/documents/{document_id}/dunning-block`

Stop the reminders of an invoice

Stop the reminders of a posted sales invoice, with why (a dispute, for instance): the reminder proposal leaves it out and lists it apart with the reason, so no letter names it and it is charged no fee and no interest while the stop holds. It stays open and payable. A person does it (the policy action release_dunning; an agent key answers 403). 409 dunning_block_exists when its reminders are stopped already, 409 dunning_block_not_invoice for another document. Needs an Idempotency-Key.


Required scope	`post` (`admin` implies every scope)
Idempotency-Key	required
Operation id	`block_reminders_v1_documents__document_id__dunning_block_post`

Parameters

In	Name	Type	Required	Description
path	`document_id`	string	yes	Document id (uuid) or number, e.g. `INV-2026-000001`.

Request body

application/json (required): DunningBlockInput

Field	Type	Required	Description
`reason`	string	yes	Why the reminders stop. (min length 1; max length 500)

Example request

curl -X POST "$ERP_URL/v1/documents/INV-2026-000001/dunning-block" \
  -H "Authorization: Bearer $ERP_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
  "reason": "The customer disputes the delivered quantity"
}'

Responses

Status	Meaning	Body
201	Created	`DunningBlockState`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
409	The request conflicts with the data: an `Idempotency-Key` reused with a different request, a closed period, or an integrity rule of the database (`conflict`, `integrity_violation`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "block": {
    "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "number": "string",
    "reason": "string",
    "blocked_by": {},
    "blocked_at": "2026-09-21T09:30:00Z"
  }
}

`DELETE /v1/documents/{document_id}/dunning-block`

Resume the reminders of an invoice

Lift the stop: the invoice is due its next reminder again as if it had not been stopped (interest runs from its due date or the last day a letter charged, as before). The stop and who lifted it stay on record. A person does it; 409 dunning_block_missing when its reminders are not stopped.


Required scope	`post` (`admin` implies every scope)
Idempotency-Key	not used
Operation id	`resume_reminders_v1_documents__document_id__dunning_block_delete`

Parameters

In	Name	Type	Required	Description
path	`document_id`	string	yes	Document id (uuid) or number, e.g. `INV-2026-000001`.

Example request

curl -X DELETE "$ERP_URL/v1/documents/INV-2026-000001/dunning-block" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	OK	`DunningBlockState`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
409	The request conflicts with the data: an `Idempotency-Key` reused with a different request, a closed period, or an integrity rule of the database (`conflict`, `integrity_violation`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "block": {
    "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "number": "string",
    "reason": "string",
    "blocked_by": {},
    "blocked_at": "2026-09-21T09:30:00Z"
  }
}

`GET /v1/entities/{entity}/customers/{party}/activity`

Get a customer's activity statement: invoices, credit notes and payments

What the customer owes us and how it came about: per currency, the opening balance on start, every invoice, credit note and payment received up to end (with a payment's reversal and a later application of an amount on account or a credit note) with the running balance, and the closing balance, in the currency of each movement. open_items are the items still open at the end of end, as on the open-items statement of that day (GET .../statement?as_of=); closing_functional is the customer's balance on the receivables control account in the functional currency, the statement's reconciliation.control_balance.

It is read from the customer's own lines on the receivables control account, so the closing balance is the one in the books. Read-only: it posts nothing, it is not archived and it is not a request for payment. 404 for an unknown entity or customer (a vendor is not a customer: its statement is GET .../vendors/{party}/statement), 422 when start is after end.


Required scope	`read` (`admin` implies every scope)
Operation id	`get_customer_activity_v1_entities__entity__customers__party__activity_get`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).
path	`party`	string	yes	Customer code, e.g. `C-DE`, or its id. A vendor is not a customer: its statement is `GET .../vendors/{party}/statement`.
query	`start`	string (date)	yes	The first day of the period, ISO 8601. What the customer owed before it is the opening balance.
query	`end`	string (date)	yes	The last day of the period, ISO 8601, not before `start`.
query	`format`	`"csv"` \| `"json"` \| `"pdf"`		`json` (default): the statement; `csv`: one row per movement with the opening and closing balance of each currency; `pdf`: an A4 PDF in the customer's language (`language` chooses another), rendered now and not stored. (default `"json"`)
query	`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"` or null		`format=pdf` only: `de`, `fr`, `it`, `en` or `sv`. Omitted: the customer's language, else the language of its country.
query	`download`	boolean		`csv` and `pdf`: `true` sends the file as an attachment. (default `false`)

Example request

curl "$ERP_URL/v1/entities/CH01/customers/C-DE/activity?start=2026-07-01&end=2026-09-30" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	JSON (the statement), CSV (its movements) or the PDF in the customer's language.	`CustomerActivity`, `text/csv`, `application/pdf`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "entity": "string",
  "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "party_code": "string",
  "party": "string",
  "start": "2026-09-21",
  "end": "2026-09-21",
  "language": "de",
  "currencies": [
    {
      "currency": "string",
      "opening": "string",
      "increases": "string",
      "decreases": "string",
      "closing": "string",
      "lines": [
        null
      ]
    }
  ],
  "functional_currency": "string",
  "closing_functional": "string",
  "open_items": [
    {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": "string",
      "kind": "payment_on_account",
      "document_date": "2026-09-21",
      "due_date": "2026-09-21",
      "currency": "string",
      "amount": "string",
      "open": "string",
      "open_functional": "0.00",
      "reserved": false,
      "days_overdue": 1,
      "bucket": "string"
    }
  ]
}

`POST /v1/entities/{entity}/customers/{party}/reminders`

Make a reminder letter to a customer

Make the letter to the customer in currency (omitted: the one currency it is due a reminder in, its own of several), dated today in the entity's country with today's amounts: it names the customer's invoices in that currency that are due a reminder (all of them, or documents), at the highest level they reached (each invoice's own when they differ), and asks for their open amount within 10 days. The PDF is in the customer's language (language chooses another) and is archived with its SHA-256 (the document archive, kind dunning_notice); the letter never changes. Then send it (POST /v1/reminders/{id}/send) or record how it was handed over (POST /v1/reminders/{id}/mark-sent): the next level counts from that day.

The letter deducts what the customer has to its credit in the currency and not yet applied (credit notes with something open, receipts' amounts on account), as far as no letter still standing deducted it already: the letters together never ask for less than is owed.

A person makes it: the policy action release_dunning is denied to agents, and an agent key answers 403 whatever the policy says. It claims no fee and no interest and posts nothing. 409 no_reminder_due when nothing is due, 409 reminder_covered_by_credits when the customer's credits cover the invoices asked for, 422 reminder_not_due for an invoice asked for that is not, 422 reminder_currency_needed when no currency is named and the customer is due reminders in several, none its own, 422 reminder_in_future or reminder_backdated for an as_of other than today. Needs an Idempotency-Key.


Required scope	`post` (`admin` implies every scope)
Idempotency-Key	required
Operation id	`create_reminder_v1_entities__entity__customers__party__reminders_post`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).
path	`party`	string	yes	Customer code, e.g. `C-DE`, or its id. A vendor is not a customer: its statement is `GET .../vendors/{party}/statement`.

Request body

application/json (required): ReminderCreateInput

Field	Type	Description
`as_of`	string (date) or null	The day of the letter: today in the entity's country, the only day a letter is dated (its amounts are today's). Omitted: today.
`currency`	string or null	The currency of the letter. Omitted: the one the customer (or the invoices named) is due a reminder in; of several, the customer's own (422 `reminder_currency_needed` when it is not one of them). (min length 3; max length 3)
`documents`	array of string (uuid) or null	Only these invoices (each must be due a reminder); omitted: every invoice of the customer in the currency that is due one. (min items 1)
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"` or null	Language of the letter; omitted: the customer's language.

Example request

curl -X POST "$ERP_URL/v1/entities/CH01/customers/C-DE/reminders" \
  -H "Authorization: Bearer $ERP_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{}'

Responses

Status	Meaning	Body
201	Created	`ReminderOut`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
409	The request conflicts with the data: an `Idempotency-Key` reused with a different request, a closed period, or an integrity rule of the database (`conflict`, `integrity_violation`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "entity": "string",
  "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "party_code": "string",
  "party": "string",
  "currency": "string",
  "level": 1,
  "letter_date": "2026-09-21",
  "deadline_date": "2026-09-21",
  "language": "de",
  "total": "string",
  "fee": "0.00",
  "charge": {
    "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "number": "string",
    "status": "string",
    "charged": true
  },
  "file": {
    "file_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "filename": "string",
    "sha256": "string",
    "size": 1
  },
  "created_by": {},
  "created_at": "2026-09-21T09:30:00Z",
  "items": [
    {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": "string",
      "level": 1,
      "due_date": "2026-09-21",
      "days_overdue": 1,
      "open_amount": "string",
      "flat_fee": "0.00",
      "interest": "0.00",
      "interest_rate": "string",
      "interest_from": "2026-09-21",
      "interest_until": "2026-09-21",
      "interest_parts": [
        null
      ]
    }
  ],
  "dispatches": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "channel": "email",
      "handed_over_on": "2026-09-21",
      "recipients": [
        "string"
      ],
      "subject": "string",
      "message_id": "string",
      "sent_by": {},
      "sent_at": "2026-09-21T09:30:00Z"
    }
  ],
  "state": "handed_over",
  "withdrawal": {
    "reason": "string",
    "withdrawn_by": {},
    "withdrawn_at": "2026-09-21T09:30:00Z"
  },
  "email": "string"
}

`GET /v1/entities/{entity}/customers/{party}/statement`

Get a customer's statement of account

The open items of one customer on a day: what the customer still owes us then.

It is the aging report restricted to the customer, from the same positions and rules: allocations (payments, credit notes, a cash discount taken) count from the day they took effect, so those dated after as_of do not; a part payment lowers the open amount of its invoice; a credit note is a negative item; a payment waiting for approval reserves its amount (reserved). items are oldest due date first, balances give the balance and the open amount per age band for each currency, and totals_functional the same in the entity's functional currency.

It ties to the ledger. reconciliation compares totals_functional.total with the customer's own lines on the receivables control account up to as_of: they are equal, apart from the period-end revaluation postings that sit on the control account (unrealised_fx, named); unexplained is zero, and anything else would be a posting no document carries. issued lists the statements of this day that were archived.

A statement is read-only: it posts nothing, and it is not a request for payment. 404 for an unknown entity or customer (a vendor is not a customer: its statement is GET .../vendors/{party}/statement). Interest accrued but not yet charged comes in a later slice of ADR-0028.


Required scope	`read` (`admin` implies every scope)
Operation id	`get_statement_v1_entities__entity__customers__party__statement_get`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).
path	`party`	string	yes	Customer code, e.g. `C-DE`, or its id. A vendor is not a customer: its statement is `GET .../vendors/{party}/statement`.
query	`as_of`	string (date)	yes	The day the statement is as of, ISO 8601, e.g. `2026-09-30`. Allocations dated after it, and documents dated after it, are not counted. Required: a statement is evidence of a day, so the day is always named.
query	`format`	`"csv"` \| `"json"` \| `"pdf"`		`json` (default): the statement; `csv`: one row per open item; `pdf`: the statement as an A4 PDF in the customer's language (`language` chooses another). For `pdf`, the archived file is returned when the statement of this customer, day and language was issued (`POST .../statement/issue`; the header `X-Statement-Archived: true` says so), otherwise the PDF is rendered now and nothing is stored. (default `"json"`)
query	`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"` or null		`format=pdf` only: `de`, `fr`, `it`, `en` or `sv`. Omitted: the customer's language, else the language of its country. Another language is another file.
query	`download`	boolean		`csv` and `pdf`: `true` sends the file as an attachment; `false` (default) inline. (default `false`)

Example request

curl "$ERP_URL/v1/entities/CH01/customers/C-DE/statement?as_of=2026-09-30" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	JSON (the statement), CSV (its open items) or the PDF in the customer's language.	`Statement`, `text/csv`, `application/pdf`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "as_of": "2026-09-25",
  "balances": [
    {
      "balance": "681.00",
      "buckets": {
        "1-30": "0.00",
        "31-60": "0.00",
        "61-90": "681.00",
        "90+": "0.00",
        "current": "0.00"
      },
      "currency": "CHF",
      "documents": 1,
      "overdue": "681.00",
      "overdue_documents": 1
    }
  ],
  "entity": "CH01",
  "functional_currency": "CHF",
  "issued": [
    {
      "file_id": "7c9e6679-7425-40de-944b-e07fc1f90ae7",
      "filename": "statement-C-CH-2026-09-25-de.pdf",
      "issued_at": "2026-09-26T08:15:00Z",
      "issued_by": {
        "id": "user:alice",
        "name": "Alice",
        "type": "human"
      },
      "language": "de",
      "sha256": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08",
      "size": 4213
    }
  ],
  "items": [
    {
      "amount": "1081.00",
      "bucket": "61-90",
      "currency": "CHF",
      "days_overdue": 86,
      "document_date": "2026-06-01",
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "due_date": "2026-07-01",
      "kind": "sales_invoice",
      "number": "INV-2026-000001",
      "open": "681.00",
      "open_functional": "681.00",
      "reserved": false
    }
  ],
  "language": "de",
  "party": "Matter Treuhand AG",
  "party_code": "C-CH",
  "party_id": "0b7d1c3e-5a4e-4d0a-9f7a-2f6d1c1d8a11",
  "reconciliation": {
    "control_account": "1100",
    "control_balance": "681.00",
    "difference": "0.00",
    "pending_settlements": "0.00",
    "totals_functional": "681.00",
    "unexplained": "0.00",
    "unrealised_fx": "0.00"
  },
  "totals_functional": {
    "1-30": "0.00",
    "31-60": "0.00",
    "61-90": "681.00",
    "90+": "0.00",
    "current": "0.00",
    "total": "681.00"
  }
}

`POST /v1/entities/{entity}/customers/{party}/statement/issue`

Issue a customer's statement: archive its PDF

Store the PDF of the customer's statement on as_of in the document archive, so that what the customer was told on that day can be shown later.

The exact bytes are kept with their SHA-256 (document.kind customer_statement, the customer, the day and the language in its metadata; the audit event is statement.issue). There is one file per customer, day and language: a second issue returns the first file with created false, and nothing is rewritten (the archive wins, as for invoices). The statement is deterministic for a day: the same ledger gives the same bytes. Download the file with GET .../statement?format=pdf and the same as_of and language.

Only a person issues, and it needs the post scope: an agent key answers 403 whatever its scopes. 422 for an as_of after today (it would not be what the customer was told), 404 for an unknown entity or customer. A statement posts nothing and is not a request for payment. Needs an Idempotency-Key.


Required scope	`post` (`admin` implies every scope)
Idempotency-Key	required
Operation id	`issue_statement_v1_entities__entity__customers__party__statement_issue_post`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).
path	`party`	string	yes	Customer code, e.g. `C-DE`, or its id. A vendor is not a customer: its statement is `GET .../vendors/{party}/statement`.

Request body

application/json (required): StatementIssueInput

Field	Type	Required	Description
`as_of`	string (date)	yes	The day the statement is as of, ISO 8601; not in the future.
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"` or null		Language of the PDF; omitted: the customer's language. Another language is another archived file.

Example request

curl -X POST "$ERP_URL/v1/entities/CH01/customers/C-DE/statement/issue" \
  -H "Authorization: Bearer $ERP_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
  "as_of": "2026-09-30"
}'

Responses

Status	Meaning	Body
201	Created	`StatementIssued`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
409	The request conflicts with the data: an `Idempotency-Key` reused with a different request, a closed period, or an integrity rule of the database (`conflict`, `integrity_violation`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "created": true,
  "download": "/v1/entities/CH01/customers/C-CH/statement?as_of=2026-09-25&format=pdf&language=de",
  "file": {
    "file_id": "7c9e6679-7425-40de-944b-e07fc1f90ae7",
    "filename": "statement-C-CH-2026-09-25-de.pdf",
    "issued_at": "2026-09-26T08:15:00Z",
    "issued_by": {
      "id": "user:alice",
      "name": "Alice",
      "type": "human"
    },
    "language": "de",
    "sha256": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08",
    "size": 4213
  }
}

`GET /v1/entities/{entity}/reminder-settings`

Get the fees and default interest of the reminder levels

What a reminder letter of each level charges: the fee per letter and the flat fee once per invoice to a business customer (in the functional currency), and the yearly default-interest rate for business customers and for consumers (actual/365, from the due date). Until settings are saved (configured false) the country's defaults apply: Switzerland and Liechtenstein 5 % a year and no fee; Germany the base rate plus 9 points (business) or 5 points (consumers), shown at today's base rate and charged at each day's (it changes on 1 January and 1 July), and EUR 40 once per invoice to a business customer; elsewhere nothing. A German rate saved at its default keeps following the base rate; a rate changed is fixed.


Required scope	`read` (`admin` implies every scope)
Operation id	`get_reminder_settings_v1_entities__entity__reminder_settings_get`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).

Example request

curl "$ERP_URL/v1/entities/CH01/reminder-settings" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	OK	`ReminderSettingsOut`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "entity": "string",
  "currency": "string",
  "configured": true,
  "levels": [
    {
      "level": 1,
      "fee": "string",
      "flat_fee": "string",
      "interest_rate": "string",
      "consumer_interest_rate": "string"
    }
  ],
  "defaults": [
    {
      "level": 1,
      "fee": "string",
      "flat_fee": "string",
      "interest_rate": "string",
      "consumer_interest_rate": "string"
    }
  ]
}

`PUT /v1/entities/{entity}/reminder-settings`

Save the fees and default interest of the reminder levels

Replace what each of the three levels charges (each level once; 422 reminder_settings_levels otherwise). Letters already made keep what they charged; the change is in the audit trail with the values before and after.


Required scope	`admin` (`admin` implies every scope)
Idempotency-Key	not used
Operation id	`put_reminder_settings_v1_entities__entity__reminder_settings_put`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).

Request body

application/json (required): ReminderSettingsInput

Field	Type	Required	Description
`levels`	array of `ReminderLevelFees-Input`	yes	The three levels, each once. (min items 3; max items 3)

Example request

curl -X PUT "$ERP_URL/v1/entities/CH01/reminder-settings" \
  -H "Authorization: Bearer $ERP_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "levels": [
    {
      "consumer_interest_rate": "5",
      "fee": "0",
      "flat_fee": "0",
      "interest_rate": "5",
      "level": 1
    },
    {
      "consumer_interest_rate": "5",
      "fee": "20",
      "flat_fee": "0",
      "interest_rate": "5",
      "level": 2
    },
    {
      "consumer_interest_rate": "5",
      "fee": "30",
      "flat_fee": "0",
      "interest_rate": "5",
      "level": 3
    }
  ]
}'

Responses

Status	Meaning	Body
200	OK	`ReminderSettingsOut`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
409	The request conflicts with the data: an `Idempotency-Key` reused with a different request, a closed period, or an integrity rule of the database (`conflict`, `integrity_violation`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "entity": "string",
  "currency": "string",
  "configured": true,
  "levels": [
    {
      "level": 1,
      "fee": "string",
      "flat_fee": "string",
      "interest_rate": "string",
      "consumer_interest_rate": "string"
    }
  ],
  "defaults": [
    {
      "level": 1,
      "fee": "string",
      "flat_fee": "string",
      "interest_rate": "string",
      "consumer_interest_rate": "string"
    }
  ]
}

`GET /v1/entities/{entity}/reminders`

List the reminder letters

The letters made in the entity, oldest first, with the invoices each named, each hand-over and its state (unsent, out_of_date, handed_over, withdrawn).


Required scope	`read` (`admin` implies every scope)
Operation id	`list_reminders_v1_entities__entity__reminders_get`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).
query	`party`	string or null		Only this customer's (code or id).
query	`document`	string (uuid) or null		Only the letters naming this invoice (its id).

Example request

curl "$ERP_URL/v1/entities/CH01/reminders" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	OK	array of `ReminderOut`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

[
  {
    "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "entity": "string",
    "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "party_code": "string",
    "party": "string",
    "currency": "string",
    "level": 1,
    "letter_date": "2026-09-21",
    "deadline_date": "2026-09-21",
    "language": "de",
    "total": "string",
    "fee": "0.00",
    "charge": {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": null,
      "status": "string",
      "charged": true
    },
    "file": {
      "file_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "filename": "string",
      "sha256": "string",
      "size": 1
    },
    "created_by": {},
    "created_at": "2026-09-21T09:30:00Z",
    "items": [
      {
        "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
        "number": "string",
        "level": 1,
        "due_date": "2026-09-21",
        "days_overdue": 1,
        "open_amount": "string",
        "flat_fee": "0.00",
        "interest": "0.00",
        "interest_rate": null,
        "interest_from": null,
        "interest_until": null,
        "interest_parts": [
          null
        ]
      }
    ],
    "dispatches": [
      {
        "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
        "channel": "email",
        "handed_over_on": "2026-09-21",
        "recipients": [
          null
        ],
        "subject": null,
        "message_id": null,
        "sent_by": {},
        "sent_at": "2026-09-21T09:30:00Z"
      }
    ],
    "state": "handed_over",
    "withdrawal": {
      "reason": "string",
      "withdrawn_by": {},
      "withdrawn_at": "2026-09-21T09:30:00Z"
    },
    "email": "string"
  }
]

`GET /v1/entities/{entity}/reminders/proposal`

List the customers due a reminder letter

Which customers are due a reminder letter today (in the entity's country; as_of says which day that is), one row per customer and currency, with the invoices it would name and its level: 1 payment reminder, 2 second reminder, 3 final reminder (levels says when each is due: a Swiss entity reminds 10 days after the due date, then 20 days after the reminder was handed over, then 10; a German one 7, 14 and 10). An invoice is due its next level when it is open today and long enough past its due date, or since the last letter that named it was handed over. There is no other day: the clock runs on real time and the amounts are today's. unsent lists the letters made and not handed over yet: they start no clock, so the next level waits for them. out_of_date lists those that can no longer be sent (an amount on them changed, or they are more than 7 days old): withdraw them.

Read-only; no fee and no interest is claimed. A customer that is another entity of the organization is not reminded.


Required scope	`read` (`admin` implies every scope)
Operation id	`get_reminder_proposal_v1_entities__entity__reminders_proposal_get`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).

Example request

curl "$ERP_URL/v1/entities/CH01/reminders/proposal" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	OK	`ReminderProposal`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "entity": "string",
  "as_of": "2026-09-21",
  "levels": [
    {
      "level": 1,
      "days_after": 1,
      "deadline_days": 1
    }
  ],
  "due": [
    {
      "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "party_code": "string",
      "party": "string",
      "currency": "string",
      "level": 1,
      "language": "de",
      "total": "string",
      "fee": "0.00",
      "email": "string",
      "invoices": [
        null
      ],
      "credits": [
        null
      ]
    }
  ],
  "unsent": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "entity": "string",
      "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "party_code": "string",
      "party": "string",
      "currency": "string",
      "level": 1,
      "letter_date": "2026-09-21",
      "deadline_date": "2026-09-21",
      "language": "de",
      "total": "string",
      "fee": "0.00",
      "charge": null,
      "file": {
        "file_id": null,
        "filename": null,
        "sha256": null,
        "size": null
      },
      "created_by": {},
      "created_at": "2026-09-21T09:30:00Z",
      "items": [
        null
      ],
      "dispatches": [
        null
      ],
      "state": "handed_over",
      "withdrawal": null,
      "email": "string"
    }
  ],
  "out_of_date": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "entity": "string",
      "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "party_code": "string",
      "party": "string",
      "currency": "string",
      "level": 1,
      "letter_date": "2026-09-21",
      "deadline_date": "2026-09-21",
      "language": "de",
      "total": "string",
      "fee": "0.00",
      "charge": null,
      "file": {
        "file_id": null,
        "filename": null,
        "sha256": null,
        "size": null
      },
      "created_by": {},
      "created_at": "2026-09-21T09:30:00Z",
      "items": [
        null
      ],
      "dispatches": [
        null
      ],
      "state": "handed_over",
      "withdrawal": null,
      "email": "string"
    }
  ],
  "blocked": [
    {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": "string",
      "party_code": "string",
      "party": "string",
      "currency": "string",
      "due_date": "2026-09-21",
      "days_overdue": 1,
      "open": "string",
      "reason": "string",
      "blocked_by": {},
      "blocked_at": "2026-09-21T09:30:00Z"
    }
  ],
  "sending_configured": true
}

`GET /v1/entities/{entity}/vendors/{party}/statement`

Get a vendor's statement: what we owe, by bill, credit note and payment

What we owe the vendor and how it came about: per currency, the opening balance on start, every bill, credit note and payment up to end with the running balance, and the closing balance, in the currency of each movement (a vendor billing in euros has a block in euros). open_items are the bills and credit notes still open at the end of end, as in the payables aging; closing_functional is the vendor's balance on the payables control account in the functional currency.

It is read from the vendor's own lines on the payables control account, so the closing balance is the one in the books; compare it with the closing balance of the statement the vendor sent. their_reference is the vendor's own number of each bill. Read-only: it posts nothing. 404 for an unknown entity or vendor (a customer is not a vendor), 422 when start is after end.


Required scope	`read` (`admin` implies every scope)
Operation id	`get_vendor_statement_v1_entities__entity__vendors__party__statement_get`

Parameters

In	Name	Type	Required	Description
path	`entity`	string	yes	Entity code, e.g. `CH01` (`GET /v1/entities`).
path	`party`	string	yes	Vendor code, e.g. `V-BM`, or its id. A customer is not a vendor.
query	`start`	string (date)	yes	The first day of the period, ISO 8601. What we owed before it is the opening balance.
query	`end`	string (date)	yes	The last day of the period, ISO 8601, not before `start`.
query	`format`	`"csv"` \| `"json"` \| `"pdf"`		`json` (default): the statement; `csv`: one row per movement with the opening and closing balance of each currency; `pdf`: an A4 PDF in the vendor's language (`language` chooses another), rendered now and not stored. (default `"json"`)
query	`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"` or null		`format=pdf` only: `de`, `fr`, `it`, `en` or `sv`.
query	`download`	boolean		`csv` and `pdf`: `true` sends the file as an attachment. (default `false`)

Example request

curl "$ERP_URL/v1/entities/CH01/vendors/V-BM/statement?start=2026-07-01&end=2026-09-30" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	JSON (the statement), CSV (its movements) or the PDF in the vendor's language.	`VendorStatement`, `text/csv`, `application/pdf`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "entity": "string",
  "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "party_code": "string",
  "party": "string",
  "start": "2026-09-21",
  "end": "2026-09-21",
  "language": "de",
  "currencies": [
    {
      "currency": "string",
      "opening": "string",
      "increases": "string",
      "decreases": "string",
      "closing": "string",
      "lines": [
        null
      ]
    }
  ],
  "functional_currency": "string",
  "closing_functional": "string",
  "open_items": [
    {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": "string",
      "kind": "payment_on_account",
      "document_date": "2026-09-21",
      "due_date": "2026-09-21",
      "currency": "string",
      "amount": "string",
      "open": "string",
      "open_functional": "0.00",
      "reserved": false,
      "days_overdue": 1,
      "bucket": "string"
    }
  ]
}

`GET /v1/reminders/{notice_id}`

Get a reminder letter

The letter, the invoices it names, its file, its hand-overs and its state. 404 when unknown.


Required scope	`read` (`admin` implies every scope)
Operation id	`get_reminder_v1_reminders__notice_id__get`

Parameters

In	Name	Type	Required	Description
path	`notice_id`	string (uuid)	yes	Reminder letter id (`GET /v1/entities/{entity}/reminders`).

Example request

curl "$ERP_URL/v1/reminders/3fa85f64-5717-4562-b3fc-2c963f66afa6" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	OK	`ReminderOut`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "entity": "string",
  "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "party_code": "string",
  "party": "string",
  "currency": "string",
  "level": 1,
  "letter_date": "2026-09-21",
  "deadline_date": "2026-09-21",
  "language": "de",
  "total": "string",
  "fee": "0.00",
  "charge": {
    "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "number": "string",
    "status": "string",
    "charged": true
  },
  "file": {
    "file_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "filename": "string",
    "sha256": "string",
    "size": 1
  },
  "created_by": {},
  "created_at": "2026-09-21T09:30:00Z",
  "items": [
    {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": "string",
      "level": 1,
      "due_date": "2026-09-21",
      "days_overdue": 1,
      "open_amount": "string",
      "flat_fee": "0.00",
      "interest": "0.00",
      "interest_rate": "string",
      "interest_from": "2026-09-21",
      "interest_until": "2026-09-21",
      "interest_parts": [
        null
      ]
    }
  ],
  "dispatches": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "channel": "email",
      "handed_over_on": "2026-09-21",
      "recipients": [
        "string"
      ],
      "subject": "string",
      "message_id": "string",
      "sent_by": {},
      "sent_at": "2026-09-21T09:30:00Z"
    }
  ],
  "state": "handed_over",
  "withdrawal": {
    "reason": "string",
    "withdrawn_by": {},
    "withdrawn_at": "2026-09-21T09:30:00Z"
  },
  "email": "string"
}

`POST /v1/reminders/{notice_id}/mark-sent`

Record that a reminder letter was handed over

Record that a person handed the letter over outside this system: by their own e-mail, by post, on the customer's portal. Nothing is sent. The first hand-over starts the clock of the next level. Only a person records (the policy action send_document; an agent key answers 403). 409 reminder_withdrawn for a withdrawn letter; 422 for a day before the letter (handover_before_document), after today (handover_in_future) or more than 7 days ago (handover_too_old): the clock of the next level runs on real days. Needs an Idempotency-Key.


Required scope	`post` (`admin` implies every scope)
Idempotency-Key	required
Operation id	`mark_reminder_sent_v1_reminders__notice_id__mark_sent_post`

Parameters

In	Name	Type	Required	Description
path	`notice_id`	string (uuid)	yes	Reminder letter id (`GET /v1/entities/{entity}/reminders`).

Request body

application/json (required): ReminderMarkSentInput

Field	Type	Required	Description
`channel`	`"email"` \| `"other"` \| `"portal"` \| `"post"`	yes	`email` (from a person's own mailbox), `post`, `portal` or `other`.
`recipient`	string	yes	Who got it. (min length 1; max length 200)
`handed_over_on`	string (date)	yes	The day it was handed over: not before the letter, not after today, and within the last 7 days.

Example request

curl -X POST "$ERP_URL/v1/reminders/3fa85f64-5717-4562-b3fc-2c963f66afa6/mark-sent" \
  -H "Authorization: Bearer $ERP_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
  "channel": "post",
  "handed_over_on": "2026-10-10",
  "recipient": "Berlin GmbH"
}'

Responses

Status	Meaning	Body
201	Created	`ReminderOut`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
409	The request conflicts with the data: an `Idempotency-Key` reused with a different request, a closed period, or an integrity rule of the database (`conflict`, `integrity_violation`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "entity": "string",
  "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "party_code": "string",
  "party": "string",
  "currency": "string",
  "level": 1,
  "letter_date": "2026-09-21",
  "deadline_date": "2026-09-21",
  "language": "de",
  "total": "string",
  "fee": "0.00",
  "charge": {
    "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "number": "string",
    "status": "string",
    "charged": true
  },
  "file": {
    "file_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "filename": "string",
    "sha256": "string",
    "size": 1
  },
  "created_by": {},
  "created_at": "2026-09-21T09:30:00Z",
  "items": [
    {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": "string",
      "level": 1,
      "due_date": "2026-09-21",
      "days_overdue": 1,
      "open_amount": "string",
      "flat_fee": "0.00",
      "interest": "0.00",
      "interest_rate": "string",
      "interest_from": "2026-09-21",
      "interest_until": "2026-09-21",
      "interest_parts": [
        null
      ]
    }
  ],
  "dispatches": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "channel": "email",
      "handed_over_on": "2026-09-21",
      "recipients": [
        "string"
      ],
      "subject": "string",
      "message_id": "string",
      "sent_by": {},
      "sent_at": "2026-09-21T09:30:00Z"
    }
  ],
  "state": "handed_over",
  "withdrawal": {
    "reason": "string",
    "withdrawn_by": {},
    "withdrawn_at": "2026-09-21T09:30:00Z"
  },
  "email": "string"
}

`GET /v1/reminders/{notice_id}/pdf`

Download a reminder letter

The archived PDF of the letter, as it was made (checked against its SHA-256, which the header X-Content-SHA256 carries).


Required scope	`read` (`admin` implies every scope)
Operation id	`get_reminder_pdf_v1_reminders__notice_id__pdf_get`

Parameters

In	Name	Type	Required	Description
path	`notice_id`	string (uuid)	yes	Reminder letter id (`GET /v1/entities/{entity}/reminders`).
query	`download`	boolean		`true` sends the file as an attachment; `false` inline. (default `false`)

Example request

curl "$ERP_URL/v1/reminders/3fa85f64-5717-4562-b3fc-2c963f66afa6/pdf" \
  -H "Authorization: Bearer $ERP_KEY"

Responses

Status	Meaning	Body
200	The PDF.	`application/pdf`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

`POST /v1/reminders/{notice_id}/send`

Send a reminder letter by e-mail

E-mail the archived letter to the customer, as an invoice is sent: to to (only the customer's own addresses) or its billing address, within the organization's hourly limit. The hand-over is recorded with the message id; the next level counts from today.

Only a person sends (the policy action send_document; an agent key answers 403). 409 in a test copy (it never e-mails customers, who may be real ones), reminder_withdrawn for a withdrawn letter, reminder_out_of_date when an amount on it changed since its day or it is more than 7 days old (withdraw it and make a new one), and when this server has no mail server (download the letter instead); 422 for an address that is not the customer's; 429 beyond the hourly limit; 502 when the mail server refuses, and nothing is recorded. Needs an Idempotency-Key.


Required scope	`post` (`admin` implies every scope)
Idempotency-Key	required
Operation id	`send_reminder_v1_reminders__notice_id__send_post`

Parameters

In	Name	Type	Required	Description
path	`notice_id`	string (uuid)	yes	Reminder letter id (`GET /v1/entities/{entity}/reminders`).

Request body

application/json (required): ReminderSendInput

Field	Type	Required	Description
`to`	array of string or null		Addresses of the customer (as for an invoice); omitted: its billing address. (min items 1; max items 5)
`message`	string or null		A text placed before the standard text. (max length 1000)

Example request

curl -X POST "$ERP_URL/v1/reminders/3fa85f64-5717-4562-b3fc-2c963f66afa6/send" \
  -H "Authorization: Bearer $ERP_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{}'

Responses

Status	Meaning	Body
201	Created	`ReminderOut`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
409	The request conflicts with the data: an `Idempotency-Key` reused with a different request, a closed period, or an integrity rule of the database (`conflict`, `integrity_violation`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`
429	A per-organization limit was reached, e.g. messages sent per hour (`rate_limited`, with `retry_after_seconds`).	`ErrorEnvelope`

Example response (shape)

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "entity": "string",
  "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "party_code": "string",
  "party": "string",
  "currency": "string",
  "level": 1,
  "letter_date": "2026-09-21",
  "deadline_date": "2026-09-21",
  "language": "de",
  "total": "string",
  "fee": "0.00",
  "charge": {
    "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "number": "string",
    "status": "string",
    "charged": true
  },
  "file": {
    "file_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "filename": "string",
    "sha256": "string",
    "size": 1
  },
  "created_by": {},
  "created_at": "2026-09-21T09:30:00Z",
  "items": [
    {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": "string",
      "level": 1,
      "due_date": "2026-09-21",
      "days_overdue": 1,
      "open_amount": "string",
      "flat_fee": "0.00",
      "interest": "0.00",
      "interest_rate": "string",
      "interest_from": "2026-09-21",
      "interest_until": "2026-09-21",
      "interest_parts": [
        null
      ]
    }
  ],
  "dispatches": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "channel": "email",
      "handed_over_on": "2026-09-21",
      "recipients": [
        "string"
      ],
      "subject": "string",
      "message_id": "string",
      "sent_by": {},
      "sent_at": "2026-09-21T09:30:00Z"
    }
  ],
  "state": "handed_over",
  "withdrawal": {
    "reason": "string",
    "withdrawn_by": {},
    "withdrawn_at": "2026-09-21T09:30:00Z"
  },
  "email": "string"
}

`POST /v1/reminders/{notice_id}/withdraw`

Withdraw a reminder letter not handed over

Withdraw a letter that was not handed over (out of date, or made by mistake), with why. The withdrawal is written once: the letter is never sent or recorded after it, and the invoices it named are due their next letter again as if it had not been made. Only a person withdraws (the policy action release_dunning; an agent key answers 403). 409 reminder_handed_over once it was handed over, reminder_withdrawn when it was withdrawn already. Needs an Idempotency-Key.


Required scope	`post` (`admin` implies every scope)
Idempotency-Key	required
Operation id	`withdraw_reminder_v1_reminders__notice_id__withdraw_post`

Parameters

In	Name	Type	Required	Description
path	`notice_id`	string (uuid)	yes	Reminder letter id (`GET /v1/entities/{entity}/reminders`).

Request body

application/json (required): ReminderWithdrawInput

Field	Type	Required	Description
`reason`	string	yes	Why it is withdrawn. (min length 1; max length 500)

Example request

curl -X POST "$ERP_URL/v1/reminders/3fa85f64-5717-4562-b3fc-2c963f66afa6/withdraw" \
  -H "Authorization: Bearer $ERP_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
  "reason": "The customer paid part of it meanwhile"
}'

Responses

Status	Meaning	Body
201	Created	`ReminderOut`
401	Missing or invalid API key (`unauthorized`).	`ErrorEnvelope`
403	The caller lacks the required scope (`missing_right`, with `scope`), the key belongs to no person where a person is needed (`forbidden`), or the approval policy denies the action (`policy_denied`, with `action` and `rule_id`).	`ErrorEnvelope`
404	The resource does not exist, or belongs to another organization (`not_found`).	`ErrorEnvelope`
409	The request conflicts with the data: an `Idempotency-Key` reused with a different request, a closed period, or an integrity rule of the database (`conflict`, `integrity_violation`).	`ErrorEnvelope`
422	Validation failed: the error envelope (`validation_failed`). For a malformed body or parameter its message is in sentences ("Line 2: the quantity must be above zero") and `fields` lists each error with pydantic's `loc`, `type` and `msg` beside its sentence (`message`) and its parts, to word it in another language: `items` (`name` and `number` from 1: line 2), `field` (its name as sent) and the `rule` it breaks with its `limit`, `count` and `choices` (none for a validator's own sentence); FastAPI's own `detail` list stays beside the envelope.	`HTTPValidationError`

Example response (shape)

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "entity": "string",
  "party_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "party_code": "string",
  "party": "string",
  "currency": "string",
  "level": 1,
  "letter_date": "2026-09-21",
  "deadline_date": "2026-09-21",
  "language": "de",
  "total": "string",
  "fee": "0.00",
  "charge": {
    "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "number": "string",
    "status": "string",
    "charged": true
  },
  "file": {
    "file_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "filename": "string",
    "sha256": "string",
    "size": 1
  },
  "created_by": {},
  "created_at": "2026-09-21T09:30:00Z",
  "items": [
    {
      "document_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "number": "string",
      "level": 1,
      "due_date": "2026-09-21",
      "days_overdue": 1,
      "open_amount": "string",
      "flat_fee": "0.00",
      "interest": "0.00",
      "interest_rate": "string",
      "interest_from": "2026-09-21",
      "interest_until": "2026-09-21",
      "interest_parts": [
        null
      ]
    }
  ],
  "dispatches": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "channel": "email",
      "handed_over_on": "2026-09-21",
      "recipients": [
        "string"
      ],
      "subject": "string",
      "message_id": "string",
      "sent_by": {},
      "sent_at": "2026-09-21T09:30:00Z"
    }
  ],
  "state": "handed_over",
  "withdrawal": {
    "reason": "string",
    "withdrawn_by": {},
    "withdrawn_at": "2026-09-21T09:30:00Z"
  },
  "email": "string"
}

Schemas

`ActivityCurrency`

The movements of one currency, from the opening to the closing balance.

Field	Type	Required	Description
`currency`	string	yes	ISO 4217 currency of the amounts.
`opening`	string	yes	What we owed at the start of the first day.
`increases`	string	yes	The sum of the positive movements.
`decreases`	string	yes	The sum of the negative movements (a negative amount).
`closing`	string	yes	What we owed at the end of the last day: `opening + increases + decreases`. Compare it with the closing balance of the statement the vendor sent.
`lines`	array of `ActivityLine`	yes	The movements, oldest first.

`ActivityLine`

One movement on the vendor's account: a bill, a credit note, a payment.

Field	Type	Required	Description
`day`	string (date)	yes	The day it was booked.
`kind`	`"application"` \| `"credit_note"` \| `"invoice"` \| `"other"` \| `"payment"` \| `"payment_reversal"` \| `"write_off"`	yes	`invoice` (the vendor's bill), `credit_note`, `payment` (what we paid, or a refund received), `payment_reversal`, `application` (an amount on account or a credit note applied to a bill later, ADR-0045: one line off the payment or credit note, one on the bill), `write_off` (a customer invoice written off as uncollectable), or `other` (an opening balance or a manual entry).
`reference`	string	yes	Our number: the bill's, the payment's or the entry's.
`their_reference`	string or null	yes	The vendor's own number of the bill or credit note, to find it on the vendor's statement.
`document_id`	string (uuid) or null	yes	The bill or credit note it concerns.
`document_number`	string or null	yes	Our number of that bill or credit note (for a payment: the one it settles).
`entry_id`	string (uuid)	yes	The journal entry that booked it.
`amount`	string	yes	In the currency of the block: positive when it raises what we owe (a bill), negative when it lowers it (a payment, a credit note).
`balance`	string	yes	What we owe after it: the running balance.

`CustomerActivity`

A customer's activity statement: what the customer owes us, by invoice, credit note and payment, between two days.

Field	Type	Required	Description
`entity`	string	yes	Entity code.
`party_id`	string (uuid)	yes	Id of the customer.
`party_code`	string	yes	Code of the customer.
`party`	string	yes	Name of the customer.
`start`	string (date)	yes	The first day of the period.
`end`	string (date)	yes	The last day of the period.
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"`	yes	The language of its PDF: the customer's, else the one spoken in its country.
`currencies`	array of `CustomerActivityCurrency`	yes	One block per currency the customer has movements or a balance in, by code: the currency of each invoice, credit note and payment.
`functional_currency`	string	yes	The entity's functional currency.
`closing_functional`	string	yes	What the customer owes at the end of `end` in the functional currency: its lines on the receivables control account, revaluations included (the `control_balance` of the open-items statement of that day).
`open_items`	array of `StatementItem`	yes	The invoices, credit notes and amounts on account still open at the end of `end`, oldest due date first (credit notes negative): the open-items statement of that day.

`CustomerActivityCurrency`

The movements of one currency, from the opening to the closing balance.

Field	Type	Required	Description
`currency`	string	yes	ISO 4217 currency of the amounts.
`opening`	string	yes	What the customer owed at the start of the first day.
`increases`	string	yes	The sum of the positive movements.
`decreases`	string	yes	The sum of the negative movements (a negative amount).
`closing`	string	yes	What the customer owed at the end of the last day: `opening + increases + decreases`. A negative amount is a credit of the customer.
`lines`	array of `CustomerActivityLine`	yes	The movements, oldest first.

`CustomerActivityLine`

One movement on the customer's account: an invoice, a credit note, a payment received.

Field	Type	Required	Description
`day`	string (date)	yes	The day it was booked.
`kind`	`"application"` \| `"credit_note"` \| `"invoice"` \| `"other"` \| `"payment"` \| `"payment_reversal"` \| `"write_off"`	yes	`invoice`, `credit_note`, `payment` (a payment received, or a refund paid out), `payment_reversal`, `application` (an amount on account or a credit note applied to an invoice later, ADR-0045: one line off the payment or credit note, one on the invoice), or `other` (an opening balance or a manual entry).
`reference`	string	yes	Our number: the invoice's, the credit note's, the payment's or the entry's.
`document_id`	string (uuid) or null	yes	The invoice or credit note it concerns.
`document_number`	string or null	yes	The number of that invoice or credit note (for a payment: the one it pays).
`entry_id`	string (uuid)	yes	The journal entry that booked it.
`amount`	string	yes	In the currency of the block: positive when it raises what the customer owes (an invoice), negative when it lowers it (a payment, a credit note).
`balance`	string	yes	What the customer owes after it: the running balance.

`DunningBlockInput`

Field	Type	Required	Description
`reason`	string	yes	Why the reminders stop. (min length 1; max length 500)

`DunningBlockOut`

The reminders of an invoice are stopped (for instance while the customer disputes it).

Field	Type	Required	Description
`document_id`	string (uuid)	yes	Id of the invoice.
`number`	string	yes	Invoice number.
`reason`	string	yes	Why the reminders stop.
`blocked_by`	object	yes	Who stopped them: type, id and name.
`blocked_at`	string (date-time)	yes	When (UTC).

`DunningBlockState`

Whether the reminders of an invoice are stopped.

Field	Type	Required	Description
`document_id`	string (uuid)	yes	Id of the invoice.
`block`	`DunningBlockOut` or null	yes	The stop while it holds; null when reminders go out as usual.

`DunningLevelOut`

One level of reminder and when it is due.

Field	Type	Required	Description
`level`	integer	yes	1 payment reminder, 2 second reminder, 3 final reminder.
`days_after`	integer	yes	Level 1: days after the due date; later levels: days after the previous letter was handed over.
`deadline_days`	integer	yes	Days the letter gives to pay, from its day.

`InterestPart`

Part of an invoice's default interest that one rate covers, when the rate changed in the span: a German company's default rates follow the base rate, which changes on 1 January and 1 July, and the days on each side of the change are charged at their own rate.

Field	Type	Required	Description
`interest_rate`	string	yes	The yearly rate in percent of these days.
`interest_from`	string (date)	yes	The part runs from the day after this one.
`interest_until`	string (date)	yes	The last day of the part.
`interest`	string	yes	The interest of these days, in the invoice's currency.

`ReminderBlocked`

An open invoice whose reminders a person stopped: no letter names it while the stop holds.

Field	Type	Required	Description
`document_id`	string (uuid)	yes	Id of the invoice.
`number`	string	yes	Invoice number.
`party_code`	string	yes	Code of the customer.
`party`	string	yes	Name of the customer.
`currency`	string	yes	ISO 4217 currency.
`due_date`	string (date)	yes	Due date.
`days_overdue`	integer	yes	Days past the due date today (0 or less: not due).
`open`	string	yes	What is open today.
`reason`	string	yes	Why the reminders are stopped.
`blocked_by`	object	yes	Who stopped them: type, id and name.
`blocked_at`	string (date-time)	yes	When (UTC).

`ReminderChargeOut`

The sales invoice that books a letter's fees and interest, made at its first hand-over.

Field	Type	Required	Description
`document_id`	string (uuid)	yes	Id of the invoice.
`number`	string or null	yes	Its number; null while it waits for approval.
`status`	string	yes	`posted`, `pending_approval`, `rejected` (by the approver, or withdrawn from approval), `draft` (a rejected invoice reopened) or `void` (reopened and voided).
`charged`	boolean	yes	False once the invoice is rejected or void: the letter's charges were not booked, and a later letter charges the same interest days and flat fees again.

`ReminderCreateInput`

Field	Type	Description
`as_of`	string (date) or null	The day of the letter: today in the entity's country, the only day a letter is dated (its amounts are today's). Omitted: today.
`currency`	string or null	The currency of the letter. Omitted: the one the customer (or the invoices named) is due a reminder in; of several, the customer's own (422 `reminder_currency_needed` when it is not one of them). (min length 3; max length 3)
`documents`	array of string (uuid) or null	Only these invoices (each must be due a reminder); omitted: every invoice of the customer in the currency that is due one. (min items 1)
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"` or null	Language of the letter; omitted: the customer's language.

`ReminderCredit`

What the customer has to its credit in the letter's currency, deducted from what the letter asks for: a credit note with something open, or a receipt's amount on account (ADR-0045). Each credit is deducted once: what a letter still standing (not withdrawn, naming an invoice still open that no later letter names) deducted is not deducted again.

Field	Type	Required	Description
`kind`	`"payment_on_account"` \| `"sales_credit_note"`	yes	`sales_credit_note`, or `payment_on_account`: what is left on account of a receipt, not yet applied to an invoice.
`document_id`	string (uuid)	yes	Id of the credit note, or of the receipt.
`number`	string	yes	Number of the credit note or the receipt.
`date`	string (date)	yes	Date of the credit note or the receipt.
`open`	string	yes	What the letter deducts of it (positive): what is left of it today, less what letters still standing deducted already. An application waiting for approval reserves its amount.

`ReminderDispatchOut`

Field	Type	Required	Description
`id`	string (uuid)	yes	Id of the hand-over.
`channel`	`"email"` \| `"other"` \| `"portal"` \| `"post"` \| `"system_email"`	yes	`system_email` (this server sent it) or what a person recorded: `email`, `post`, `portal`, `other`.
`handed_over_on`	string (date)	yes	The day it was handed over.
`recipients`	array of string	yes	To whom.
`subject`	string or null	yes	Subject of the e-mail; null for a recorded one.
`message_id`	string or null	yes	`Message-ID` of the e-mail; null otherwise.
`sent_by`	object	yes	Who: type, id and name.
`sent_at`	string (date-time)	yes	When it was sent or recorded (UTC).

`ReminderDue`

A customer that is due a reminder letter in one currency.

Field	Type	Required	Description
`party_id`	string (uuid)	yes	Id of the customer.
`party_code`	string	yes	Code of the customer.
`party`	string	yes	Name of the customer.
`currency`	string	yes	The currency of the letter.
`level`	integer	yes	The letter's level: the highest next level of its invoices.
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"`	yes	The customer's language: that of the letter.
`total`	string	yes	What the letter would ask for: the invoices' open amounts less `credits`, plus `fee` and the flat fees and interest of the invoices. A customer whose credits cover its overdue invoices is due no letter.
`fee`	string		The fee of the letter's level, in its currency (converted from the functional currency at today's rate); 0 for none. (default `"0.00"`)
`email`	string or null	yes	Where an e-mail would go by default: the customer's billing address.
`invoices`	array of `ReminderInvoice`	yes	The invoices due a reminder.
`credits`	array of `ReminderCredit`		The customer's credit notes with something open and receipts' amounts on account in the currency, as far as no letter still standing deducted them, which the letter deducts.

`ReminderFile`

The archived PDF of a letter.

Field	Type	Required	Description
`file_id`	string (uuid)	yes	Id of the archived file (`document.id`).
`filename`	string	yes	File name, e.g. `reminder-C-DE-2026-10-10-1.pdf`.
`sha256`	string	yes	SHA-256 of the archived bytes.
`size`	integer	yes	Size in bytes.

`ReminderInvoice`

An overdue invoice and where its reminders stand.

Field	Type	Required	Description
`document_id`	string (uuid)	yes	Id of the invoice.
`number`	string	yes	Invoice number.
`document_date`	string (date)	yes	Invoice date.
`due_date`	string (date)	yes	Due date.
`days_overdue`	integer	yes	Days past the due date today.
`currency`	string	yes	ISO 4217 currency.
`open`	string	yes	What is open today, in the invoice's currency.
`last_level`	integer	yes	The level of the last letter that named it; 0 for none.
`last_sent_on`	string (date) or null	yes	The day that letter was first handed over; null when none was, or never.
`next_level`	integer	yes	The level the next letter gives it.
`flat_fee`	string		The flat fee the letter charges once for this invoice (a business customer; Germany: EUR 40, § 288 para. 5 BGB), in its currency; 0 for none. (default `"0.00"`)
`interest`	string		Default interest the letter charges on this invoice, in its currency: actual/365 on what was open each day from `interest_from` (exclusive) to `interest_until`; 0 for none. (default `"0.00"`)
`interest_rate`	string or null		The yearly rate in percent (when it changed in the span, that of the letter's day: see `interest_parts`); null when no interest is charged.
`interest_from`	string (date) or null		The interest runs from the day after this one: the due date, or the last day an earlier letter charged interest for (no day is charged twice).
`interest_until`	string (date) or null		The last day the interest covers: the letter's day.
`interest_parts`	array of `InterestPart`		When the rate changed in the span (the German base rate on 1 January or 1 July), the parts at each rate, in order, adding up to `interest`; empty when one rate covers it all.

`ReminderItemOut`

Field	Type	Required	Description
`document_id`	string (uuid)	yes	Id of the invoice.
`number`	string	yes	Invoice number.
`level`	integer	yes	The level the invoice reached with this letter.
`due_date`	string (date)	yes	Its due date.
`days_overdue`	integer	yes	Days past the due date on the letter's day.
`open_amount`	string	yes	What was open on the letter's day.
`flat_fee`	string		The flat fee charged for it. (default `"0.00"`)
`interest`	string		The default interest charged on it. (default `"0.00"`)
`interest_rate`	string or null		Yearly rate in percent.
`interest_from`	string (date) or null		The interest runs from the day after this one.
`interest_until`	string (date) or null		The last day the interest covers.
`interest_parts`	array of `InterestPart`		When the rate changed in the span (the German base rate on 1 January or 1 July), the parts at each rate, in order, adding up to `interest`; empty when one rate covers it all.

`ReminderLevelFees-Input`

What a reminder of one level charges.

Field	Type	Required	Description
`level`	integer	yes	1 payment reminder, 2 second, 3 final reminder. (min 1; max 3)
`fee`	decimal string	yes	Fee per letter of this level, in the company's functional currency (a letter in another currency converts it at the letter's day); 0 for none. (min 0)
`flat_fee`	decimal string	yes	Flat fee charged once per invoice to a business customer, in the functional currency (Germany: EUR 40 on the first reminder, § 288 para. 5 BGB); 0 for none. When the charge of the letter that set it is rejected or voided, the next letter charges it. (min 0)
`interest_rate`	decimal string	yes	Default interest for business customers, percent a year (actual/365), from the due date; 0 for none. (min 0; max 100)
`consumer_interest_rate`	decimal string	yes	Default interest for consumers (customers that are not a business), percent a year; 0 for none. (min 0; max 100)

`ReminderLevelFees-Output`

What a reminder of one level charges.

Field	Type	Required	Description
`level`	integer	yes	1 payment reminder, 2 second, 3 final reminder. (min 1; max 3)
`fee`	string	yes	Fee per letter of this level, in the company's functional currency (a letter in another currency converts it at the letter's day); 0 for none.
`flat_fee`	string	yes	Flat fee charged once per invoice to a business customer, in the functional currency (Germany: EUR 40 on the first reminder, § 288 para. 5 BGB); 0 for none. When the charge of the letter that set it is rejected or voided, the next letter charges it.
`interest_rate`	string	yes	Default interest for business customers, percent a year (actual/365), from the due date; 0 for none.
`consumer_interest_rate`	string	yes	Default interest for consumers (customers that are not a business), percent a year; 0 for none.

`ReminderMarkSentInput`

Field	Type	Required	Description
`channel`	`"email"` \| `"other"` \| `"portal"` \| `"post"`	yes	`email` (from a person's own mailbox), `post`, `portal` or `other`.
`recipient`	string	yes	Who got it. (min length 1; max length 200)
`handed_over_on`	string (date)	yes	The day it was handed over: not before the letter, not after today, and within the last 7 days.

`ReminderOut`

A reminder letter: what it asked for, its file and its hand-overs.

Field	Type	Required	Description
`id`	string (uuid)	yes	Id of the letter.
`entity`	string	yes	Entity code.
`party_id`	string (uuid)	yes	Id of the customer.
`party_code`	string	yes	Code of the customer.
`party`	string	yes	Name of the customer.
`currency`	string	yes	ISO 4217 currency.
`level`	integer	yes	1 payment reminder, 2 second reminder, 3 final reminder.
`letter_date`	string (date)	yes	The day of the letter.
`deadline_date`	string (date)	yes	The day by which it asks for payment.
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"`	yes	The language of the letter.
`total`	string	yes	What it asks for: the open amounts of its invoices less the customer's credits it deducts, plus its fee and the flat fees and interest of its invoices, on the letter's day.
`fee`	string		The fee of its level; 0 for none. (default `"0.00"`)
`charge`	`ReminderChargeOut` or null		The sales invoice of its fees and interest (outside VAT), made when it was first handed over; null before, or when it charges nothing.
`file`	`ReminderFile`	yes	The archived PDF.
`created_by`	object	yes	Who made it.
`created_at`	string (date-time)	yes	When.
`items`	array of `ReminderItemOut`	yes	The invoices it names.
`dispatches`	array of `ReminderDispatchOut`	yes	Each hand-over, oldest first. Empty: made but not sent, which starts no clock for the next level.
`state`	`"handed_over"` \| `"out_of_date"` \| `"unsent"` \| `"withdrawn"`	yes	`unsent` (made, not handed over, still right: send or record it), `out_of_date` (not handed over, and an amount on it changed since or it is more than 7 days old: it cannot be sent; withdraw it and make a new one), `handed_over` or `withdrawn`.
`withdrawal`	`ReminderWithdrawalOut` or null		Who withdrew it, when and why; null when nobody did.
`email`	string or null	yes	Where an e-mail would go by default: the customer's billing address.

`ReminderProposal`

Which customers are due a reminder letter today, and the letters not yet sent.

Field	Type	Required	Description
`entity`	string	yes	Entity code.
`as_of`	string (date)	yes	Today, in the entity's country: the day of the letters.
`levels`	array of `DunningLevelOut`	yes	The levels and when each is due.
`due`	array of `ReminderDue`	yes	One row per customer and currency that is due a letter, by customer code.
`unsent`	array of `ReminderOut`	yes	Letters made, not handed over yet and still right: send or record them, or the next level never comes.
`out_of_date`	array of `ReminderOut`		Letters not handed over that are out of date (an amount on them changed, or they are more than 7 days old): they cannot be sent and hold back the next letter until they are withdrawn.
`blocked`	array of `ReminderBlocked`		Open invoices whose reminders a person stopped (a dispute): left out of every letter, with why.
`sending_configured`	boolean	yes	Whether this server sends e-mail (false in a test copy, which never does).

`ReminderSendInput`

Field	Type	Required	Description
`to`	array of string or null		Addresses of the customer (as for an invoice); omitted: its billing address. (min items 1; max items 5)
`message`	string or null		A text placed before the standard text. (max length 1000)

`ReminderSettingsInput`

Field	Type	Required	Description
`levels`	array of `ReminderLevelFees-Input`	yes	The three levels, each once. (min items 3; max items 3)

`ReminderSettingsOut`

The fees and default interest of each reminder level of a company.

Field	Type	Required	Description
`entity`	string	yes	Entity code.
`currency`	string	yes	The functional currency the fees are in.
`configured`	boolean	yes	Whether a person saved settings; false: the country's defaults apply.
`levels`	array of `ReminderLevelFees-Output`	yes	The three levels, in order.
`defaults`	array of `ReminderLevelFees-Output`	yes	The country's defaults: Switzerland and Liechtenstein 5 % a year and no fee; Germany the base rate plus 9 points (business) or 5 points (consumers), shown at today's base rate and charged at each day's (split where it changes, on 1 January or 1 July), and EUR 40 once per invoice to a business customer; elsewhere nothing.

`ReminderWithdrawInput`

Field	Type	Required	Description
`reason`	string	yes	Why it is withdrawn. (min length 1; max length 500)

`ReminderWithdrawalOut`

Field	Type	Required	Description
`reason`	string	yes	Why it was withdrawn.
`withdrawn_by`	object	yes	Who: type, id and name.
`withdrawn_at`	string (date-time)	yes	When (UTC).

`Statement`

A customer's statement of account: the open items on a day.

Field	Type	Required	Description
`entity`	string	yes	Entity code.
`party_id`	string (uuid)	yes	Id of the customer.
`party_code`	string	yes	Code of the customer.
`party`	string	yes	Name of the customer.
`as_of`	string (date)	yes	The day the statement is as of.
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"`	yes	The language of its PDF: the customer's, else the one spoken in its country.
`items`	array of `StatementItem`	yes	Open items, oldest due date first; credit notes are negative items.
`balances`	array of `StatementBalance`	yes	The balance and its age structure per currency, by currency code.
`functional_currency`	string	yes	The entity's functional currency.
`totals_functional`	map of string	yes	The open amount per age band and `total` in the functional currency: the figures `reconciliation` ties to the ledger.
`reconciliation`	`StatementReconciliation`	yes	The total against the customer's lines on the control account.
`issued`	array of `StatementFile`	yes	Statements of this customer and day that were archived (`POST .../issue`), oldest first, one per language.

`StatementBalance`

The open items of one currency: the balance and what is overdue, by age.

Field	Type	Required	Description
`currency`	string	yes	ISO 4217 currency.
`balance`	string	yes	The open amount in this currency; credit notes reduce it.
`overdue`	string	yes	The part of the balance that is past its due date (every band but `current`).
`documents`	integer	yes	How many items are listed in this currency.
`overdue_documents`	integer	yes	How many of them are past their due date (`bucket` is not `current`).
`buckets`	map of string	yes	The open amount per age band, every band present: `current`, `1-30`, `31-60`, `61-90`, `90+`. They add up to `balance`.

`StatementFile`

A statement kept in the document archive.

Field	Type	Required	Description
`file_id`	string (uuid)	yes	Id of the archived file (`document.id`).
`filename`	string	yes	File name, e.g. `statement-C-CH-2026-09-30-de.pdf`.
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"`	yes	Language the PDF was issued in.
`sha256`	string	yes	SHA-256 of the archived bytes.
`size`	integer	yes	Size in bytes.
`issued_by`	object	yes	Who issued it: type, id and name.
`issued_at`	string (date-time)	yes	When it was archived.

`StatementIssueInput`

Field	Type	Required	Description
`as_of`	string (date)	yes	The day the statement is as of, ISO 8601; not in the future.
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"` or null		Language of the PDF; omitted: the customer's language. Another language is another archived file.

`StatementIssued`

The result of issuing a statement.

Field	Type	Required	Description
`file`	`StatementFile`	yes	The archived PDF.
`created`	boolean	yes	True when this call archived the file; false when the statement of this customer, day and language was archived before and that file is returned (the archive wins: what the customer was told is not rewritten).
`download`	string	yes	The path that returns the PDF (`GET .../statement?format=pdf`), which serves the archived file for this day and language.

`StatementItem`

One open item: an invoice or bill, or a credit note or a payment's amount on account as a negative item.

Field	Type	Required	Description
`document_id`	string (uuid)	yes	Id of the invoice, bill or credit note; of the receipt or payment for an amount on account.
`number`	string	yes	Document number, e.g. `INV-2026-000012`.
`kind`	`"payment_on_account"` \| `"purchase_bill"` \| `"purchase_credit_note"` \| `"sales_credit_note"` \| `"sales_invoice"`	yes	`sales_invoice` or `sales_credit_note` on a customer's statement, `purchase_bill` or `purchase_credit_note` on a vendor's; `payment_on_account` on either: what is left on account of a receipt or payment, not yet applied (never overdue).
`document_date`	string (date)	yes	Document date.
`due_date`	string (date)	yes	Due date.
`currency`	string	yes	ISO 4217 currency of the amounts.
`amount`	string	yes	Gross total, negative for a credit note.
`open`	string	yes	What is open on `as_of`, negative for a credit note: the total less the allocations dated on or before `as_of` (payments, credit notes, a cash discount taken).
`open_functional`	string		The carrying amount the ledger holds for the item in the entity's functional currency on `as_of`, negative for a credit note. (default `"0.00"`)
`reserved`	boolean		True when payments waiting for approval reserve the whole open amount: `open` is zero, the ledger still carries the item. (default `false`)
`days_overdue`	integer	yes	Days past the due date on `as_of`; 0 when not yet due.
`bucket`	string	yes	`current`, `1-30`, `31-60`, `61-90` or `90+` days overdue.

`StatementReconciliation`

The statement's total against the ledger: the customer's lines on the receivables control account up to the day.

Field	Type	Required	Description
`control_account`	string	yes	Code of the receivables control account.
`control_balance`	string	yes	The balance of this customer's lines on the control account in the ledger as of `as_of`, in the functional currency (what the customer owes us).
`totals_functional`	string	yes	The statement's total in the functional currency: the sum of the items' `open_functional`, the carrying amounts the ledger holds.
`difference`	string	yes	`control_balance` less `totals_functional`.
`unrealised_fx`	string	yes	Entries of source `fx` (period-end revaluations) on the customer's control lines up to `as_of` that no reversal has cancelled yet: they sit on the control account but on no document.
`pending_settlements`	string	yes	A memo: the functional amount of payments and applications waiting for approval on the listed items (an application on both of its items). They reserve the open amount in the document currency but are not booked, so they are in neither `control_balance` nor `totals_functional`.
`unexplained`	string	yes	`difference` less `unrealised_fx`: zero when the statement ties to the ledger; anything else is a posting on the control account that no document carries.

`VendorStatement`

A vendor's statement: what we owe the vendor, by bill, credit note and payment.

Field	Type	Required	Description
`entity`	string	yes	Entity code.
`party_id`	string (uuid)	yes	Id of the vendor.
`party_code`	string	yes	Code of the vendor.
`party`	string	yes	Name of the vendor.
`start`	string (date)	yes	The first day of the period.
`end`	string (date)	yes	The last day of the period.
`language`	`"de"` \| `"en"` \| `"fr"` \| `"it"` \| `"sv"`	yes	The language of its PDF: the vendor's, else the one spoken in its country.
`currencies`	array of `ActivityCurrency`	yes	One block per currency the vendor has movements or a balance in, by code; the vendor's own currency is among them when it has any.
`functional_currency`	string	yes	The entity's functional currency.
`closing_functional`	string	yes	What we owe the vendor at the end of `end` in the functional currency: its lines on the payables control account, revaluations included.
`open_items`	array of `StatementItem`	yes	The bills and credit notes still open at the end of `end`, oldest due date first (credit notes negative): the same open items as the payables aging.