Build Symfony REST API with OpenAPI and Swagger UI Integration

This guide shows you how to build your first REST API endpoint (/api/users/{id}) in Symfony 7.2, document it with OpenAPI YAML, and integrate Swagger UI for interactive testing. Using nelmio/api-doc-bundle and a hybrid approach, we’ll keep code clean, generate openapi.yaml, and set up docs with minimal effort. Follow these steps from scratch to create a fully documented API!

Prerequisites

  • PHP 8.2+
  • MySQL 8.0.42
  • Composer
  • Symfony CLI
  • Node.js and npm (for Swagger UI)