Overview

OneBooks is a multi-tenant accounting platform. The developer platform lets your product — a POS, an e-commerce store, an ERP, anything that produces financial data — connect to a OneBooks business, push and read accounting documents, and react to changes in real time.

How an integration works

1. A business connects your app through standard OAuth 2.0 authorization code + PKCE. The business owner reviews the scopes you request and approves.
2. You call the REST API with the resulting access token. The token is bound to that one business — every request is automatically tenant-scoped, and you never send a business identifier.
3. OneBooks calls you back via webhooks when invoices, payments, customers or credit notes change.

Everything you push lands in a real double-entry ledger: an imported invoice posts the same journal entries as one created in the OneBooks app, and shows up in the business’s P&L, balance sheet and tax reports immediately.

Base URLs

Surface	URL
API	https://api.getonebooks.com
Authorization page (user-facing consent)	https://app.getonebooks.com/oauth/authorize
Developer console	developer.getonebooks.com/console
OAuth discovery document	https://api.getonebooks.com/.well-known/oauth-authorization-server

Prefer the discovery document over hard-coding endpoints — it lists every OAuth endpoint plus the API base URL.

Start building

Getting startedFrom zero to your first authenticated API call, step by step.

AuthenticationThe full OAuth 2.0 + PKCE flow: authorize, exchange, refresh, revoke.

WebhooksSigned event deliveries with automatic retries.

API referenceEvery partner endpoint, request and response schema.

The developer journey

Access to the platform is gated — you build and test first, then go live:

1. Create a developer account and complete the NDA + developer agreement.
2. Create an organization and register your app to get credentials.
3. Build against sandbox businesses — throwaway but fully real OneBooks tenants (up to 3 per organization).
4. Submit for review. Once approved, your app can connect to any OneBooks business.

Integration patterns

Not sure how to model your data in an accounting system? The integration patterns guide covers the three most common shapes — POS sales (daily summary vs. per-document push), e-commerce order-to-invoice mapping, and ERP master-data sync — with runnable examples.