Sebastian Ramirez's Python web framework with first-class async, OpenAPI, and type hints. The default for new Python APIs in 2026.
From Wikipedia
FastAPI is a web framework for building HTTP-based service APIs in Python 3.8+. It uses Pydantic and type hints to validate, serialize and deserialize data. FastAPI also automatically generates OpenAPI documentation for APIs built with it. It was first released in 2018.