Authentication

Authenticate every request with one server-side API key.

Bearer authentication

The preferred method is the Authorization header with the exact Bearer prefix. API keys use the fn_ prefix followed by a random 32-character identifier.

Authorization: Bearer fn_your_api_key

Key safety

FINAP keys authorize billable requests across your subscribed services. Store them in a secret manager or server environment variable, rotate compromised keys immediately, and use separate keys for separate applications.

Authentication errors

401

Missing API key

Neither Authorization nor X-API-Key was present.

401

Invalid or revoked API key

The key does not exist, was revoked, or is malformed.

402

Insufficient balance

The account cannot cover the service price.