FastAPI is a modern, fast (high-performance) web framework for building APIs with Python based on standard Python type hints. It's designed to be easy to use, while offering high performance and automatic API documentation. Fast performance on par with NodeJS and Go, easy to use and learn, fast to code, standards-based compatibility with OpenAPI (Swagger) and JSON Schema, async built-in support for operations, and excellent documentation and learning resources make it stand out. As a coroutine-based framework, FastAPI offers significant benefits including high concurrency to handle thousands of concurrent connections efficiently, resource efficiency with lower memory footprint compared to traditional threaded frameworks, better I/O handling with non-blocking I/O operations for database queries, external API calls, and file operations, and scalable performance that maintains responsiveness under high load conditions.
FastAPI has seen tremendous growth in recent years, with more GitHub stars than both Flask and Django as of 2025, rapidly becoming the preferred choice for new Python web projects, and seeing strong adoption by major tech companies (Microsoft, Uber, Netflix). FastAPI is currently mainly used in our AI services and deployed with Kubernetes.