The WordPress REST API has been part of WordPress core since version 4.7. It transforms WordPress from a self-contained CMS into a content platform that can serve data to any application that can make an HTTP request — mobile apps, static front ends, third-party services, or another WordPress site. For publishers evaluating headless architecture or building integrations, understanding what the API provides (and how to use it) is increasingly essential.

WPGraphQL is an open-source WordPress plugin that adds a fully featured GraphQL API to any WordPress installation. It transforms WordPress from a self-contained CMS into a content platform queryable by any GraphQL client — a Next.js front end, a mobile app, a Hugo build process, or any other consumer capable of making HTTP requests. The REST API built into WordPress core works, but GraphQL solves problems the REST API does not handle elegantly: over-fetching unnecessary fields, under-fetching requiring multiple round-trips, and querying relational data efficiently.