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REST API

Basis exposes a RESTful JSON API for integrating with external applications, automating data entry, and building custom reporting.

Authentication

The API uses Bearer token authentication.

Generating an API Key

Go to Settings → API Keys → New.
Give the key a name (e.g. "ERP Integration").
Set an expiry date (optional).
Copy the key — it is shown only once.

Using the Token

Include the token in every request header:

Authorization: Bearer YOUR_API_KEY

Base URL

https://your-domain.com/api/v1

For Cloud edition: https://app.basis-apps.net/api/v1

Common Endpoints

Parties

Method	Endpoint	Description
GET	`/parties`	List parties
GET	`/parties/{id}`	Get a party
POST	`/parties`	Create a party
PUT	`/parties/{id}`	Update a party

Sales Invoices

Method	Endpoint	Description
GET	`/sales-invoices`	List invoices
GET	`/sales-invoices/{id}`	Get an invoice
POST	`/sales-invoices`	Create an invoice
POST	`/sales-invoices/{id}/post`	Post a draft invoice
POST	`/sales-invoices/{id}/void`	Void a posted invoice

Receipts

Method	Endpoint	Description
GET	`/receipts`	List receipts
POST	`/receipts`	Create and post a receipt

Items

Method	Endpoint	Description
GET	`/items`	List items
GET	`/items/{id}`	Get an item
POST	`/items`	Create an item

Request / Response Format

All requests and responses use application/json.

Example — Create a Sales Invoice

Request:

POST /api/v1/sales-invoices
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

{
  "date": "2026-05-01",
  "customer_id": "party-uuid",
  "due_date": "2026-05-31",
  "lines": [
    {
      "item_id": "item-uuid",
      "qty": 5,
      "unit_price": 100000,
      "tax_category": "VAT11"
    }
  ]
}

Response:

{
  "id": "inv-uuid",
  "invoice_number": "INV-2026-0042",
  "status": "draft",
  "total": 555000,
  "tax": 55000
}

Rate Limits

Plan	Requests per minute
Server (per installation)	600
Cloud Starter	120
Cloud Professional	600
Cloud Enterprise	Unlimited

Webhooks

Configure webhooks to receive real-time notifications when documents are created or status changes:

Go to Settings → Webhooks → New.
Enter your endpoint URL.
Select events to subscribe to.
Basis sends a POST with a JSON payload to your URL.

SDK

An official TypeScript/JavaScript SDK is available:

npm install @basis-apps/sdk

See the SDK documentation on GitHub.

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