The Modern Treasury API is organized around REST. Our API has predictable resource-oriented URLs, accepts JSON request bodies, returns JSON-encoded responses, and uses standard HTTP response codes, authentication, and verbs. You can use the Modern Treasury API in a sandbox environment without affecting your live data or interacting with real banking networks. The API key you use to authenticate determines whether a request runs in live mode or in the sandbox.
By default, sandbox environments are configured for payment service provider (PSP) use. If you're a first-time user getting started with Modern Treasury through the PSP, refer to the Payments Quickstart.