---
title: "API Reference"
description: "The complete Billabex public API reference, generated from its OpenAPI specification."
canonical: https://developer.billabex.com/en/api-reference/
lang: en
alternate: https://developer.billabex.com/fr/reference-api/
last-updated: 2026-09-13
---

# API Reference

> The complete Billabex public API reference, generated from its OpenAPI specification.

Source: https://developer.billabex.com/en/api-reference/
Language: English (en)
French version: https://developer.billabex.com/fr/reference-api/

Use the Billabex REST API to manage customer accounts, contacts, invoices, credit notes, payment follow-ups and account tasks.

Authorize with OAuth 2.1 Authorization Code and PKCE (S256). Send Authorization: Bearer <access_token> and request only the scopes your integration needs. Organization data requires user authorization.

Then GET /api/public/v1/organizations to obtain your organizationId. GET /api/public/v1/accounts and GET /api/public/v1/invoices list your data with cursor pagination. Read RateLimit and RateLimit-Policy, and wait for Retry-After on HTTP 429.

## First request, no authentication required

```bash
curl -i 'https://next.billabex.com/api/public/v1/status'
```

- [OpenAPI](https://developer.billabex.com/openapi.json)
- [OAuth](https://developer.billabex.com/en/guides/oauth/)
- [Guides](https://developer.billabex.com/en/guides/getting-started/)

---

Billabex developer portal. OpenAPI specification: https://developer.billabex.com/openapi.json.
Agent instructions: https://developer.billabex.com/llms.txt. Complete documentation: https://developer.billabex.com/llms-full.txt.