What is REST API? — UK Software Development Guide

4 min readJune 2025ClickMasters Technical TeamReviewed by James Whitmore, CTO
what is a rest api

Direct Answer

A REST API (Representational State Transfer Application Programming Interface) is a web service that follows the REST architectural style. REST APIs use HTTP methods (GET, POST, PUT, PATCH, DELETE) to perform operations on resources identified by URLs. REST has become the dominant API style because of its simplicity, use of standard HTTP, and wide tooling support.

Rest-api in the UK

REST is the standard for UK government APIs: HMRC Making Tax Digital, Companies House, GOV.UK Notify, GOV.UK Pay, NHS Spine, and GP Connect all use REST with JSON payloads. The GDS API design guide mandates REST for government APIs. OpenAPI 3.0 (Swagger) is the documentation standard. UK GDPR considerations: personal data in URL parameters is a security risk (visible in server logs and browser history) — REST APIs handling personal data should use POST bodies rather than query strings for sensitive identifiers.

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