REST API
A web API designed around the REST architectural style, exposing resources at URLs and manipulating them with standard HTTP methods.
Most SaaS platforms, from CRMs to ad platforms, expose REST APIs, so their quality decides how easily data can be synced, automated and reported without manual exports or fragile workarounds.
An integration calls GET /v3/contacts?updated_after=2026-10-01 on a CRM, pages through 2,000 results 100 at a time, then sends PATCH requests to update lead status, retrying after the Retry-After delay when it receives HTTP 429.
Many APIs described as RESTful skip constraints such as hypermedia, and designs vary widely between vendors. Fetching related data can take many round trips, and each client must handle rate limits, pagination and versioning.
Roy Fielding defined REST in 2000 as a set of constraints: client-server separation, stateless requests, cacheable responses, a uniform interface, layered systems and optional code on demand. In practice, resources are identified by URLs and manipulated with HTTP methods whose semantics, including safe and idempotent methods, are set by RFC 9110. Responses carry status codes and representations, typically JavaScript Object Notation (JSON), and REST APIs are often paired with a Webhook for event notifications.
Data Engineering, Intelligent Automation
Roy T. Fielding, UC Irvine — Architectural Styles and the Design of Network-based Software Architectures, Chapter 5: Representational State Transfer (REST) — https://ics.uci.edu/~fielding/pubs/dissertation/rest_arch_style.htm; MDN Web Docs — REST (Glossary) — https://developer.mozilla.org/en-US/docs/Glossary/REST