Customers

GET `/v1/customers`

List customers

customers:read

Parameter	In	Type	Required	Description
`cvr`	query	`string`	No	Exact CVR match
`email`	query	`string`	No	Exact e-mail match (blind index — no free-text search)
`externalReference`	query	`string`	No	Exact match on your own reference
`pastDue`	query	`string`	No	true = only customers currently past due (threshold-evaluated)
`limit`	query	`integer`	No	Page size, 1-200 (default 50)
`cursor`	query	`string`	No	Opaque cursor from meta.nextCursor

Request exampleNo request body

curl https://api.rieckflow.com/v1/customers \
  -H "Authorization: Bearer $RIECK_API_KEY"

const svar = await rieck.request("GET", "/v1/customers");

{
  "data": [
    {
      "id": "467a0d8d-b9b2-4df3-bf7b-17d649442890",
      "type": "company",
      "name": "Acme ApS",
      "cvr": "12345678",
      "vatNumber": null,
      "address": {
        "street": "Hovedgaden 1",
        "postalCode": "8000",
        "city": "Aarhus",
        "country": "DK"
      },
      "email": "ap@acme.example",
      "phone": "+45 70 12 34 56",
      "contactPerson": "Alex Jensen",
      "language": "da",
      "hasCpr": false,
      "externalReference": "crm-9001",
      "metadata": {
        "segment": "b2b"
      },
      "createdAt": "2026-08-04T09:32:11Z"
    }
  ],
  "meta": {
    "nextCursor": null
  }
}

200 Success envelopeapplication/json

Response fields 9

Field	Type	Description
`data[].id`	`uuid`	Stable Rieck customer id.
`data[].type`	`company \| person`	Customer type.
`data[].name`	`string`	Customer name.
`data[].address`	`object \| null`	Postal address used on documents.
`data[].hasCpr`	`boolean`	Whether Rieck has a CPR number. The number is never returned.
`data[].externalReference`	`string \| null`	Your customer reference.
`data[].metadata`	`object \| null`	Your own string key/value data.
`data[].createdAt`	`date-time`	UTC creation timestamp.
`meta.nextCursor`	`string	null`

Possible errors 5

HTTP	Code	Meaning
400	`invalid_cursor`	The cursor is malformed, expired or belongs to another list shape.
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
429	`rate_limited`	The organisation’s rate budget is exhausted.

POST `/v1/customers`

Create customer

customers:write

Request body fields 15

Field	Type	Required	Description
`type`	`string`	Yes	Resource-specific type.
`name`	`string`	Yes	Human-readable name.
`cvr`	`string`	No	Danish CVR number for a company.
`vatNumber`	`string`	No	Foreign VAT number for a non-Danish company.
`address`	`object`	No	Postal address used on documents.
`address.street`	`string`	No	Street and house number.
`address.postalCode`	`string`	No	Postal code.
`address.city`	`string`	No	City.
`address.country`	`string`	No	ISO country code or country name.
`email`	`string`	No	E-mail used for delivery and contact.
`phone`	`string`	No	Customer or contact phone number.
`contactPerson`	`string`	No	Named contact at the customer.
`language`	`string`	No	Language used for customer-facing documents.
`externalReference`	`string`	No	Your stable reference for reconciliation and idempotent imports.
`metadata`	`object`	No	Your own string key/value data. Never used for Rieck business logic.

Request exampleapplication/json

curl -X POST https://api.rieckflow.com/v1/customers \
  -H "Authorization: Bearer $RIECK_API_KEY" \
  -H "Idempotency-Key: order-2041" \
  -H "Content-Type: application/json" \
  -d '{
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678",
    "email": "ap@acme.example"
  }'

const svar = await rieck.request("POST", "/v1/customers", {
  body: {
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678",
    "email": "ap@acme.example"
  },
});

{
  "data": {
    "id": "467a0d8d-b9b2-4df3-bf7b-17d649442890",
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678",
    "vatNumber": null,
    "address": {
      "street": "Hovedgaden 1",
      "postalCode": "8000",
      "city": "Aarhus",
      "country": "DK"
    },
    "email": "ap@acme.example",
    "phone": "+45 70 12 34 56",
    "contactPerson": "Alex Jensen",
    "language": "da",
    "hasCpr": false,
    "externalReference": "crm-9001",
    "metadata": {
      "segment": "b2b"
    },
    "createdAt": "2026-08-04T09:32:11Z"
  }
}

201 Success envelopeapplication/json

Response fields 8

Field	Type	Description
`data.id`	`uuid`	Stable Rieck customer id.
`data.type`	`company \| person`	Customer type.
`data.name`	`string`	Customer name.
`data.address`	`object \| null`	Postal address used on documents.
`data.hasCpr`	`boolean`	Whether Rieck has a CPR number. The number is never returned.
`data.externalReference`	`string \| null`	Your customer reference.
`data.metadata`	`object \| null`	Your own string key/value data.
`data.createdAt`	`date-time`	UTC creation timestamp.

Possible errors 9

HTTP	Code	Meaning
400	`invalid_idempotency_key`	Idempotency-Key is missing or malformed.
400	`invalid_request`	The request body or parameter failed validation.
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
409	`idempotency_conflict`	The same key was used with a different request.
409	`idempotency_in_progress`	The same operation is currently being processed. Retry later.
413	`payload_too_large`	The JSON or uploaded file exceeds this endpoint’s size limit.
429	`rate_limited`	The organisation’s rate budget is exhausted.

Request body — fuldt JSON Schema

{
  "type": "object",
  "properties": {
    "type": {
      "type": "string",
      "enum": [
        "person",
        "company"
      ]
    },
    "name": {
      "type": "string",
      "minLength": 1,
      "maxLength": 200
    },
    "cvr": {
      "anyOf": [
        {
          "type": "string",
          "pattern": "^\\d{8}$"
        },
        {
          "type": "null"
        }
      ]
    },
    "vatNumber": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 20
        },
        {
          "type": "null"
        }
      ]
    },
    "address": {
      "anyOf": [
        {
          "type": "object",
          "properties": {
            "street": {
              "type": "string",
              "maxLength": 200
            },
            "postalCode": {
              "type": "string",
              "maxLength": 10
            },
            "city": {
              "type": "string",
              "maxLength": 100
            },
            "country": {
              "type": "string",
              "maxLength": 100
            }
          },
          "additionalProperties": false
        },
        {
          "type": "null"
        }
      ]
    },
    "email": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 254
        },
        {
          "type": "null"
        }
      ]
    },
    "phone": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 30
        },
        {
          "type": "null"
        }
      ]
    },
    "contactPerson": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 200
        },
        {
          "type": "null"
        }
      ]
    },
    "language": {
      "anyOf": [
        {
          "type": "string",
          "enum": [
            "da",
            "en"
          ]
        },
        {
          "type": "null"
        }
      ]
    },
    "externalReference": {
      "anyOf": [
        {
          "type": "string",
          "minLength": 1,
          "maxLength": 200
        },
        {
          "type": "null"
        }
      ]
    },
    "metadata": {
      "anyOf": [
        {
          "type": "object",
          "propertyNames": {
            "type": "string",
            "minLength": 1,
            "maxLength": 40
          },
          "additionalProperties": {
            "type": "string",
            "maxLength": 500
          }
        },
        {
          "type": "null"
        }
      ]
    }
  },
  "required": [
    "type",
    "name"
  ],
  "additionalProperties": false
}

GET `/v1/customers/{customerId}`

Get customer

customers:read

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes

Request exampleNo request body

curl https://api.rieckflow.com/v1/customers/9b2f1c1e-… \
  -H "Authorization: Bearer $RIECK_API_KEY"

const svar = await rieck.request("GET", "/v1/customers/9b2f1c1e-…");

{
  "data": {
    "id": "467a0d8d-b9b2-4df3-bf7b-17d649442890",
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678",
    "vatNumber": null,
    "address": {
      "street": "Hovedgaden 1",
      "postalCode": "8000",
      "city": "Aarhus",
      "country": "DK"
    },
    "email": "ap@acme.example",
    "phone": "+45 70 12 34 56",
    "contactPerson": "Alex Jensen",
    "language": "da",
    "hasCpr": false,
    "externalReference": "crm-9001",
    "metadata": {
      "segment": "b2b"
    },
    "createdAt": "2026-08-04T09:32:11Z"
  }
}

200 Success envelopeapplication/json

Response fields 8

Field	Type	Description
`data.id`	`uuid`	Stable Rieck customer id.
`data.type`	`company \| person`	Customer type.
`data.name`	`string`	Customer name.
`data.address`	`object \| null`	Postal address used on documents.
`data.hasCpr`	`boolean`	Whether Rieck has a CPR number. The number is never returned.
`data.externalReference`	`string \| null`	Your customer reference.
`data.metadata`	`object \| null`	Your own string key/value data.
`data.createdAt`	`date-time`	UTC creation timestamp.

Possible errors 5

HTTP	Code	Meaning
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
429	`rate_limited`	The organisation’s rate budget is exhausted.

PATCH `/v1/customers/{customerId}`

Update customer

customers:write

Partial: omitted fields kept, null clears.

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes

Request body fields 15

Field	Type	Required	Description
`type`	`string`	No	Resource-specific type.
`name`	`string`	No	Human-readable name.
`cvr`	`string`	No	Danish CVR number for a company.
`vatNumber`	`string`	No	Foreign VAT number for a non-Danish company.
`address`	`object`	No	Postal address used on documents.
`address.street`	`string`	No	Street and house number.
`address.postalCode`	`string`	No	Postal code.
`address.city`	`string`	No	City.
`address.country`	`string`	No	ISO country code or country name.
`email`	`string`	No	E-mail used for delivery and contact.
`phone`	`string`	No	Customer or contact phone number.
`contactPerson`	`string`	No	Named contact at the customer.
`language`	`string`	No	Language used for customer-facing documents.
`externalReference`	`string`	No	Your stable reference for reconciliation and idempotent imports.
`metadata`	`object`	No	Your own string key/value data. Never used for Rieck business logic.

Request exampleapplication/json

curl -X PATCH https://api.rieckflow.com/v1/customers/9b2f1c1e-… \
  -H "Authorization: Bearer $RIECK_API_KEY" \
  -H "Idempotency-Key: order-2041" \
  -H "Content-Type: application/json" \
  -d '{
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678"
  }'

const svar = await rieck.request("PATCH", "/v1/customers/9b2f1c1e-…", {
  body: {
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678"
  },
});

{
  "data": {
    "id": "467a0d8d-b9b2-4df3-bf7b-17d649442890",
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678",
    "vatNumber": null,
    "address": {
      "street": "Hovedgaden 1",
      "postalCode": "8000",
      "city": "Aarhus",
      "country": "DK"
    },
    "email": "ap@acme.example",
    "phone": "+45 70 12 34 56",
    "contactPerson": "Alex Jensen",
    "language": "da",
    "hasCpr": false,
    "externalReference": "crm-9001",
    "metadata": {
      "segment": "b2b"
    },
    "createdAt": "2026-08-04T09:32:11Z"
  }
}

200 Success envelopeapplication/json

Response fields 8

Field	Type	Description
`data.id`	`uuid`	Stable Rieck customer id.
`data.type`	`company \| person`	Customer type.
`data.name`	`string`	Customer name.
`data.address`	`object \| null`	Postal address used on documents.
`data.hasCpr`	`boolean`	Whether Rieck has a CPR number. The number is never returned.
`data.externalReference`	`string \| null`	Your customer reference.
`data.metadata`	`object \| null`	Your own string key/value data.
`data.createdAt`	`date-time`	UTC creation timestamp.

Possible errors 10

HTTP	Code	Meaning
400	`invalid_idempotency_key`	Idempotency-Key is missing or malformed.
400	`invalid_request`	The request body or parameter failed validation.
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
409	`idempotency_conflict`	The same key was used with a different request.
409	`idempotency_in_progress`	The same operation is currently being processed. Retry later.
413	`payload_too_large`	The JSON or uploaded file exceeds this endpoint’s size limit.
429	`rate_limited`	The organisation’s rate budget is exhausted.

Request body — fuldt JSON Schema

{
  "type": "object",
  "properties": {
    "type": {
      "type": "string",
      "enum": [
        "person",
        "company"
      ]
    },
    "name": {
      "type": "string",
      "minLength": 1,
      "maxLength": 200
    },
    "cvr": {
      "anyOf": [
        {
          "type": "string",
          "pattern": "^\\d{8}$"
        },
        {
          "type": "null"
        }
      ]
    },
    "vatNumber": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 20
        },
        {
          "type": "null"
        }
      ]
    },
    "address": {
      "anyOf": [
        {
          "type": "object",
          "properties": {
            "street": {
              "type": "string",
              "maxLength": 200
            },
            "postalCode": {
              "type": "string",
              "maxLength": 10
            },
            "city": {
              "type": "string",
              "maxLength": 100
            },
            "country": {
              "type": "string",
              "maxLength": 100
            }
          },
          "additionalProperties": false
        },
        {
          "type": "null"
        }
      ]
    },
    "email": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 254
        },
        {
          "type": "null"
        }
      ]
    },
    "phone": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 30
        },
        {
          "type": "null"
        }
      ]
    },
    "contactPerson": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 200
        },
        {
          "type": "null"
        }
      ]
    },
    "language": {
      "anyOf": [
        {
          "type": "string",
          "enum": [
            "da",
            "en"
          ]
        },
        {
          "type": "null"
        }
      ]
    },
    "externalReference": {
      "anyOf": [
        {
          "type": "string",
          "minLength": 1,
          "maxLength": 200
        },
        {
          "type": "null"
        }
      ]
    },
    "metadata": {
      "anyOf": [
        {
          "type": "object",
          "propertyNames": {
            "type": "string",
            "minLength": 1,
            "maxLength": 40
          },
          "additionalProperties": {
            "type": "string",
            "maxLength": 500
          }
        },
        {
          "type": "null"
        }
      ]
    }
  },
  "additionalProperties": false
}

GET `/v1/customers/{customerId}/balance`

Customer balance

customers:read

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes

Request exampleNo request body

curl https://api.rieckflow.com/v1/customers/9b2f1c1e-…/balance \
  -H "Authorization: Bearer $RIECK_API_KEY"

const svar = await rieck.request("GET", "/v1/customers/9b2f1c1e-…/balance");

{
  "data": {
    "outstandingOere": 125000,
    "overdueOere": 125000,
    "overdueCount": 1,
    "oldestDueDate": "2026-07-15",
    "daysOverdue": 20,
    "collectionsOere": 0,
    "pastDue": true
  }
}

200 Canonically computed outstanding/overdue amounts and pastDue state — use this to gate services, never the invoice status field.application/json

Response fields 5

Field	Type	Description
`data.outstandingOere`	`integer`	Total amount still owed.
`data.overdueOere`	`integer`	Amount currently overdue.
`data.oldestDueDate`	`date \| null`	Oldest unpaid due date.
`data.daysOverdue`	`integer`	Days since the oldest unpaid due date.
`data.pastDue`	`boolean`	Canonical service-gating signal.

Possible errors 5

HTTP	Code	Meaning
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
429	`rate_limited`	The organisation’s rate budget is exhausted.

GET `/v1/customers/{customerId}/statement`

Statement of account

customers:read

Ledger of invoices, credit notes, payments and reminder fees. Defaults to the last 12 months; max 1830 days.

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes
`from`	query	`string`	No	YYYY-MM-DD (default: 12 months before `to`)
`to`	query	`string`	No	YYYY-MM-DD (default: today, Europe/Copenhagen)

Request exampleNo request body

curl https://api.rieckflow.com/v1/customers/9b2f1c1e-…/statement \
  -H "Authorization: Bearer $RIECK_API_KEY"

const svar = await rieck.request("GET", "/v1/customers/9b2f1c1e-…/statement");

{
  "data": {
    "from": "2026-07-01",
    "to": "2026-08-04",
    "openingBalanceOere": 0,
    "closingBalanceOere": 156250,
    "lines": [
      {
        "date": "2026-08-04",
        "type": "invoice",
        "documentNumber": 1042,
        "reference": null,
        "amountOere": 156250,
        "balanceOere": 156250,
        "invoiceId": "9b2f1c1e-6b87-4d9b-91a0-47c8d72b8440"
      }
    ]
  }
}

200 closingBalanceOere may be NEGATIVE when the customer has overpaid — unlike /balance, which never reports less than zero owed.application/json

Response fields 3

Field	Type	Description
`data.openingBalanceOere`	`integer`	Balance carried into the selected period.
`data.closingBalanceOere`	`integer`	Balance at the end; a negative value means customer credit.
`data.lines`	`object[]`	Signed ledger movements in chronological order.

Possible errors 5

HTTP	Code	Meaning
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
429	`rate_limited`	The organisation’s rate budget is exhausted.

GET `/v1/customers/{customerId}/statement/pdf`

Statement of account (PDF)

customers:read

Rendered in the customer’s own language. Generated per request — not a WORM-stored document like an invoice.

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes
`from`	query	`string`	No	YYYY-MM-DD
`to`	query	`string`	No	YYYY-MM-DD

Request exampleNo request body

curl
TypeScript

curl https://api.rieckflow.com/v1/customers/9b2f1c1e-…/statement/pdf \
  -H "Authorization: Bearer $RIECK_API_KEY"

const svar = await rieck.request("GET", "/v1/customers/9b2f1c1e-…/statement/pdf");

200 Success envelopeapplication/pdf

Possible errors 5

HTTP	Code	Meaning
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
429	`rate_limited`	The organisation’s rate budget is exhausted.

GET `/v1/customers/{customerId}/departments`

List departments

customers:read

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes

Request exampleNo request body

curl https://api.rieckflow.com/v1/customers/9b2f1c1e-…/departments \
  -H "Authorization: Bearer $RIECK_API_KEY"

const svar = await rieck.request("GET", "/v1/customers/9b2f1c1e-…/departments");

{
  "data": [
    {
      "id": "9b2f1c1e-6b87-4d9b-91a0-47c8d72b8440",
      "customerId": "467a0d8d-b9b2-4df3-bf7b-17d649442890",
      "name": "Aarhus office",
      "contactPerson": "Alex Jensen",
      "reference": "dept-17",
      "email": "aarhus@acme.example",
      "sortOrder": 10
    }
  ]
}

200 Success envelopeapplication/json

Possible errors 5

HTTP	Code	Meaning
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
429	`rate_limited`	The organisation’s rate budget is exhausted.

POST `/v1/customers/{customerId}/departments`

Create department

customers:write

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes

Request body fields 5

Field	Type	Required	Description
`name`	`string`	Yes	Human-readable name.
`contactPerson`	`string`	No	Named contact at the customer.
`reference`	`string`	No	Field in the request payload.
`email`	`string`	No	E-mail used for delivery and contact.
`sortOrder`	`integer`	No	Field in the request payload.

Request exampleapplication/json

curl -X POST https://api.rieckflow.com/v1/customers/9b2f1c1e-…/departments \
  -H "Authorization: Bearer $RIECK_API_KEY" \
  -H "Idempotency-Key: order-2041" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Acme ApS",
    "reference": "crm-9001",
    "email": "ap@acme.example",
    "sortOrder": 1
  }'

const svar = await rieck.request("POST", "/v1/customers/9b2f1c1e-…/departments", {
  body: {
    "name": "Acme ApS",
    "reference": "crm-9001",
    "email": "ap@acme.example",
    "sortOrder": 1
  },
});

{
  "data": {
    "id": "9b2f1c1e-6b87-4d9b-91a0-47c8d72b8440",
    "customerId": "467a0d8d-b9b2-4df3-bf7b-17d649442890",
    "name": "Aarhus office",
    "contactPerson": "Alex Jensen",
    "reference": "dept-17",
    "email": "aarhus@acme.example",
    "sortOrder": 10
  }
}

201 Success envelopeapplication/json

Possible errors 10

HTTP	Code	Meaning
400	`invalid_idempotency_key`	Idempotency-Key is missing or malformed.
400	`invalid_request`	The request body or parameter failed validation.
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
409	`idempotency_conflict`	The same key was used with a different request.
409	`idempotency_in_progress`	The same operation is currently being processed. Retry later.
413	`payload_too_large`	The JSON or uploaded file exceeds this endpoint’s size limit.
429	`rate_limited`	The organisation’s rate budget is exhausted.

Request body — fuldt JSON Schema

{
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "minLength": 1,
      "maxLength": 200
    },
    "contactPerson": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 200
        },
        {
          "type": "null"
        }
      ]
    },
    "reference": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 140
        },
        {
          "type": "null"
        }
      ]
    },
    "email": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 254
        },
        {
          "type": "null"
        }
      ]
    },
    "sortOrder": {
      "type": "integer",
      "minimum": 0,
      "maximum": 9999
    }
  },
  "required": [
    "name"
  ],
  "additionalProperties": false
}

DELETE `/v1/customers/{customerId}/departments/{departmentId}`

Delete department

customers:write

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes
`departmentId`	path	`string`	Yes

Request exampleNo request body

curl
TypeScript

curl -X DELETE https://api.rieckflow.com/v1/customers/9b2f1c1e-…/departments/9b2f1c1e-… \
  -H "Authorization: Bearer $RIECK_API_KEY" \
  -H "Idempotency-Key: order-2041"

const svar = await rieck.request("DELETE", "/v1/customers/9b2f1c1e-…/departments/9b2f1c1e-…");

204 No contentNo response body

Possible errors 8

HTTP	Code	Meaning
400	`invalid_idempotency_key`	Idempotency-Key is missing or malformed.
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
409	`idempotency_conflict`	The same key was used with a different request.
409	`idempotency_in_progress`	The same operation is currently being processed. Retry later.
429	`rate_limited`	The organisation’s rate budget is exhausted.

GET `/v1/customers/{customerId}/einvoicing`

E-invoicing endpoint

customers:read

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes

Request exampleNo request body

curl https://api.rieckflow.com/v1/customers/9b2f1c1e-…/einvoicing \
  -H "Authorization: Bearer $RIECK_API_KEY"

const svar = await rieck.request("GET", "/v1/customers/9b2f1c1e-…/einvoicing");

{
  "data": {
    "id": "467a0d8d-b9b2-4df3-bf7b-17d649442890",
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678",
    "vatNumber": null,
    "address": {
      "street": "Hovedgaden 1",
      "postalCode": "8000",
      "city": "Aarhus",
      "country": "DK"
    },
    "email": "ap@acme.example",
    "phone": "+45 70 12 34 56",
    "contactPerson": "Alex Jensen",
    "language": "da",
    "hasCpr": false,
    "externalReference": "crm-9001",
    "metadata": {
      "segment": "b2b"
    },
    "createdAt": "2026-08-04T09:32:11Z"
  }
}

200 endpoint (null = this customer cannot be sent an e-invoice), the Peppol scheme derived from the number’s own form (0088 GLN, 0184 CVR, 0096 P-number) and its schemeName, plus the customer’s departments with THEIR endpoints. ⚠️ A department’s endpoint WINS over the customer’s when we send — a public authority often routes per department, and invoicing the head office is how an invoice disappears.application/json

Response fields 8

Field	Type	Description
`data.id`	`uuid`	Stable Rieck customer id.
`data.type`	`company \| person`	Customer type.
`data.name`	`string`	Customer name.
`data.address`	`object \| null`	Postal address used on documents.
`data.hasCpr`	`boolean`	Whether Rieck has a CPR number. The number is never returned.
`data.externalReference`	`string \| null`	Your customer reference.
`data.metadata`	`object \| null`	Your own string key/value data.
`data.createdAt`	`date-time`	UTC creation timestamp.

Possible errors 5

HTTP	Code	Meaning
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
429	`rate_limited`	The organisation’s rate budget is exhausted.

PUT `/v1/customers/{customerId}/einvoicing`

Set or clear the endpoint

customers:write

One field. Send endpoint: null to clear it. ⚠️ The check digit is validated SERVER-SIDE: a 13-digit number without a valid GS1 check digit is not “maybe another type” — no Danish endpoint type is 13 digits except GLN — so a typo is rejected with 422 invalid_endpoint rather than reaching the network and coming back two days later as a rejection.

Parameter	In	Type	Required	Description
`customerId`	path	`string`	Yes

Request body fields 1

Field	Type	Required	Description
`endpoint`	`string`	Yes	Field in the request payload.

Request exampleapplication/json

curl -X PUT https://api.rieckflow.com/v1/customers/9b2f1c1e-…/einvoicing \
  -H "Authorization: Bearer $RIECK_API_KEY" \
  -H "Idempotency-Key: order-2041" \
  -H "Content-Type: application/json" \
  -d '{
    "endpoint": "…"
  }'

const svar = await rieck.request("PUT", "/v1/customers/9b2f1c1e-…/einvoicing", {
  body: {
    "endpoint": "…"
  },
});

{
  "data": {
    "id": "467a0d8d-b9b2-4df3-bf7b-17d649442890",
    "type": "company",
    "name": "Acme ApS",
    "cvr": "12345678",
    "vatNumber": null,
    "address": {
      "street": "Hovedgaden 1",
      "postalCode": "8000",
      "city": "Aarhus",
      "country": "DK"
    },
    "email": "ap@acme.example",
    "phone": "+45 70 12 34 56",
    "contactPerson": "Alex Jensen",
    "language": "da",
    "hasCpr": false,
    "externalReference": "crm-9001",
    "metadata": {
      "segment": "b2b"
    },
    "createdAt": "2026-08-04T09:32:11Z"
  }
}

200 Success envelopeapplication/json

Response fields 8

Field	Type	Description
`data.id`	`uuid`	Stable Rieck customer id.
`data.type`	`company \| person`	Customer type.
`data.name`	`string`	Customer name.
`data.address`	`object \| null`	Postal address used on documents.
`data.hasCpr`	`boolean`	Whether Rieck has a CPR number. The number is never returned.
`data.externalReference`	`string \| null`	Your customer reference.
`data.metadata`	`object \| null`	Your own string key/value data.
`data.createdAt`	`date-time`	UTC creation timestamp.

Possible errors 10

HTTP	Code	Meaning
400	`invalid_idempotency_key`	Idempotency-Key is missing or malformed.
400	`invalid_request`	The request body or parameter failed validation.
401	`invalid_api_key`	The API key is missing, invalid, expired or revoked.
403	`api_not_included`	The organisation’s plan does not include API access.
403	`insufficient_scope`	The key does not have the required scope.
404	`customer_not_found`	The customer does not exist or belongs to another organisation.
409	`idempotency_conflict`	The same key was used with a different request.
409	`idempotency_in_progress`	The same operation is currently being processed. Retry later.
413	`payload_too_large`	The JSON or uploaded file exceeds this endpoint’s size limit.
429	`rate_limited`	The organisation’s rate budget is exhausted.

Request body — fuldt JSON Schema

{
  "type": "object",
  "properties": {
    "endpoint": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 20
        },
        {
          "type": "null"
        }
      ]
    }
  },
  "required": [
    "endpoint"
  ],
  "additionalProperties": false
}

Customers

GET /v1/customers

POST /v1/customers

GET /v1/customers/{customerId}

PATCH /v1/customers/{customerId}

GET /v1/customers/{customerId}/balance

GET /v1/customers/{customerId}/statement

GET /v1/customers/{customerId}/statement/pdf

GET /v1/customers/{customerId}/departments

POST /v1/customers/{customerId}/departments

DELETE /v1/customers/{customerId}/departments/{departmentId}

GET /v1/customers/{customerId}/einvoicing

PUT /v1/customers/{customerId}/einvoicing

GET `/v1/customers`

POST `/v1/customers`

GET `/v1/customers/{customerId}`

PATCH `/v1/customers/{customerId}`

GET `/v1/customers/{customerId}/balance`

GET `/v1/customers/{customerId}/statement`

GET `/v1/customers/{customerId}/statement/pdf`

GET `/v1/customers/{customerId}/departments`

POST `/v1/customers/{customerId}/departments`

DELETE `/v1/customers/{customerId}/departments/{departmentId}`

GET `/v1/customers/{customerId}/einvoicing`

PUT `/v1/customers/{customerId}/einvoicing`