OneBooks Developer Platform

The accounting API for your product

OAuth 2.0 APIs, HMAC-signed webhooks, and disposable sandboxes — everything you need to ship a production accounting integration.

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post a journal entry

$ curl -X POST https://api.getonebooks.com/journal \
    -H "Authorization: Bearer $TOKEN" \
    -H "Content-Type: application/json" \
    -d '{
      "date": "2026-08-12",
      "description": "Owner investment",
      "lines": [
        { "accountCode": "1200", "debit":  5000 },
        { "accountCode": "3000", "credit": 5000 }
      ]
    }'

HTTP/2 201
{
  "journalNumber": "JE-00042",
  "lines": [
    { "accountCode": "1200", "debit": 5000, "credit": 0 },
    { "accountCode": "3000", "debit": 0, "credit": 5000 }
  ]
}

Two calls to your first invoice

Exchange your authorization code for a token, then call the API. No SDK required.

1 · exchange your code for a token

curl -X POST https://api.getonebooks.com/oauth/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d grant_type=authorization_code \
  -d code=AUTH_CODE \
  -d client_id=YOUR_CLIENT_ID \
  -d client_secret=YOUR_CLIENT_SECRET \
  -d redirect_uri=https://yourapp.example.com/callback \
  -d code_verifier=PKCE_VERIFIER

2 · make your first API call

curl https://api.getonebooks.com/invoices \
  -H "Authorization: Bearer ACCESS_TOKEN"

OAuth 2.0 + PKCEStandards-based authorization with granular scopes.WebhooksHMAC-signed events with automatic retries.SandboxProvision disposable test businesses from the console.Guided go-liveApp review that takes you from sandbox to production.