Back to Architecture Explorer

fastapi / fastapi

FastAPI framework, high performance, easy to learn, fast to code, ready for production.

79.0k
Python
Architecture: library
main
fastapi
fastapi
__init__.py
applications.py
routing.py
dependencies
openapi
security
docs
en
es
ja
docs_src
tests
scripts
pyproject.toml
Structural Architecture

FastAPI keeps the importable package at the repository root rather than under src, and gives unusual prominence to documentation: the docs tree is multilingual and its code examples are executed as part of the test suite, so documentation cannot drift from behaviour.

  • Documentation examples stored as real, importable modules rather than inline snippets.
  • Translations organised as parallel language trees under docs.
  • OpenAPI generation kept inside the core package rather than as a plugin.

Notable Directories

/fastapi

The framework package: routing, dependency injection, parameter declaration, and OpenAPI generation.

/docs_src

Runnable example applications referenced by the documentation and exercised by tests.

/docs

Documentation content, subdivided per translated language.

/tests

The pytest suite, including tests that execute the documentation examples directly.

Build Your Own Ecosystem

Learn from fastapi's structure and craft your own software scaffolding.