Getting Started


Welcome to the Newline API docs! Here we’ll explain how to use our API to build your financial products and services. Throughout these docs, we'll provide information about the Newline platform including our product offerings, terminology, endpoints, and what we have available to test in our Sandbox environment.

About our API

The Newline API is organized around REST. With a few exceptions, our API has standard resource-oriented URLs, accepts form-encoded OR JSON-encoded request bodies, returns JSON-encoded responses, and uses standard HTTP response codes, authentication, and verbs.


How does your API design handle Idempotency?

  • For any request made to one of our endpoints, Newline requires a header parameter, listed as x_trace_id. The x_trace_id is a unique identifier, and duplicate values submitted in requests within 7 days of each other will cause the request to be rejected.

What APIs are available to me in Sandbox?

  • Newline maintains key features in Sandbox for Client quality assurance and future Customer program design. This API reference contains a Sandbox section, detailing the endpoints available and any differences when compared to production.