REST API

Swagger / OpenAPI

The interactive API documentation is available at /swagger on your Basis server. It lists every endpoint with request/response schemas and a Try it out button.

https://your-basis-server/swagger

Authentication

All API calls (except POST /auth/login) require a JWT Bearer token in the Authorization header.

Get a token

POST /auth/login
Content-Type: application/json

{
  "email": "admin@yourco.com",
  "password": "your-password"
}

Response:

{
  "token": "eyJhbGciOiJIUzI1NiIs...",
  "expiresAt": "2026-04-08T10:00:00Z"
}

Use the token

GET /sales-invoices
Authorization: Bearer eyJhbGciOiJIUzI1NiIs...
X-Business-Id: {businessId}

The X-Business-Id header identifies which company's data to operate on. You can find business IDs from GET /businesses.

Key endpoint groups

Pagination

List endpoints accept page and pageSize query parameters. Default page size is 50.

GET /sales-invoices?page=2&pageSize=25

Responses include a pagination object with totalCount, totalPages, currentPage.

Error responses

Errors follow a consistent format:

{
  "status": 400,
  "title": "Validation failed",
  "errors": {
    "date": ["The Date field is required."],
    "lines": ["At least one line is required."]
  }
}