Your keys work against two environments. Sandbox mirrors production and moves no real money, so build against it first.
Environment
Base URL
Sandbox
https://sandbox.api.fin.com
Production
https://api.fin.com
The API uses OAuth 2.0 client credentials. Exchange your client ID and secret for an access token, refresh it without re-authenticating, and send it on every request. See Issue a Token.
The full specification is published as a single YAML file. Import it into Postman, Insomnia, or a client generator to scaffold your integration.Download the OpenAPI spec (YAML)To fetch it from the command line: