Project Infrastructure

Relevant source files

• .github/workflows/build-docs.yml
• .github/workflows/contributors.yml
• .github/workflows/deploy-docs.yml
• .github/workflows/label-approved.yml
• .github/workflows/notify-translations.yml
• .github/workflows/people.yml
• .github/workflows/publish.yml
• .github/workflows/smokeshow.yml
• .github/workflows/sponsors.yml
• .github/workflows/test.yml
• .github/workflows/topic-repos.yml
• .github/workflows/translate.yml
• fastapi/applications.py
• fastapi/cli.py
• fastapi/dependencies/models.py
• fastapi/dependencies/utils.py
• fastapi/encoders.py
• fastapi/exceptions.py
• fastapi/openapi/models.py
• fastapi/openapi/utils.py
• fastapi/param_functions.py
• fastapi/params.py
• fastapi/routing.py
• fastapi/utils.py
• pyproject.toml
• tests/test_datetime_custom_encoder.py
• tests/test_dependency_wrapped.py
• tests/test_jsonable_encoder.py
• tests/test_skip_defaults.py
• uv.lock

Purpose and Scope

This document provides an overview of FastAPI's project infrastructure, including package configuration, dependency management, CI/CD pipelines, and development tooling. It describes how the project is built, tested, and released, and how developers interact with the codebase.

For information about code quality tools and pre-commit hooks, see Code Quality and Pre-commit Hooks. For details about the testing framework, see Test Framework and Coverage. For documentation build systems, see Documentation Build System.

Infrastructure Overview

FastAPI's infrastructure is built around modern Python tooling, with uv as the primary dependency manager and build tool, GitHub Actions for CI/CD automation, and pdm-backend for package building.

Infrastructure Component Overview

Sources: pyproject.toml1-341 uv.lock1-8 .github/workflows/test.yml1-212 .github/workflows/build-docs.yml1-118 .github/workflows/publish.yml1-30

Package Configuration

The project is defined in pyproject.toml which serves as the single source of truth for package metadata, dependencies, and tool configurations. For details, see Package Configuration and Dependencies.

Core Package Metadata

Configuration	Value	Description
name	fastapi	Package name on PyPI
build-backend	pdm.backend	Build system using pdm-backend
requires-python	>=3.10	Minimum Python version
dynamic	["version"]	Version read from fastapi/__init__.py

Sources: pyproject.toml1-15

Dependency Groups

FastAPI organizes dependencies into several groups for different use cases:

Dependency Group Structure

Sources: pyproject.toml44-192

Tool Configurations

The pyproject.toml file includes configurations for multiple development tools:

Tool	Configuration Section	Purpose
PDM	[tool.pdm]	Version source, distribution settings
mypy	[tool.mypy]	Type checking with Pydantic plugin
pytest	[tool.pytest]	Test execution settings
coverage	[tool.coverage.*]	Code coverage measurement
ruff	[tool.ruff.lint]	Linting rules and ignores

Sources: pyproject.toml194-340

Dependency Management with uv

FastAPI uses uv as its dependency manager, providing fast, reproducible builds through lock files. For details, see Dependency Management with uv.

uv Dependency Management Workflow

The lock file uv.lock1-8 specifies exact versions for all dependencies, ensuring reproducible builds across environments.

Common uv Commands

Sources: .github/workflows/test.yml104 .github/workflows/publish.yml26-29 pyproject.toml194-196

CI/CD Pipeline Architecture

FastAPI uses GitHub Actions for all CI/CD operations, organized into multiple workflow files that handle testing, documentation, releases, and community automation. For details, see CI/CD Pipeline.

CI/CD Workflow Dependencies

Sources: .github/workflows/test.yml1-212 .github/workflows/build-docs.yml1-118 .github/workflows/publish.yml1-30 .github/workflows/deploy-docs.yml1-83

Primary Workflows

Test Workflow

The .github/workflows/test.yml workflow runs comprehensive tests across multiple dimensions:

Matrix Dimension	Values	Purpose
OS	ubuntu-latest, macos-latest, windows-latest	Cross-platform compatibility
Python	3.10, 3.11, 3.12, 3.13, 3.14	Version compatibility
Resolution	highest, lowest-direct	Dependency range testing
Starlette Source	starlette-pypi, starlette-git	Bleeding edge testing

The workflow includes three main jobs:

1. changes: Filters paths to determine if tests are needed .github/workflows/test.yml20-43
2. test: Executes test matrix with coverage collection .github/workflows/test.yml45-121
3. benchmark: Runs performance benchmarks with CodSpeed .github/workflows/test.yml123-154
4. coverage-combine: Merges coverage reports and enforces 100% threshold .github/workflows/test.yml156-193

Sources: .github/workflows/test.yml1-212

Build Documentation Workflow

The .github/workflows/build-docs.yml workflow builds documentation for all supported languages in parallel:

Documentation Build Matrix

The workflow:

1. Determines language list using ./scripts/docs.py langs-json .github/workflows/build-docs.yml62
2. Builds each language in parallel with caching .github/workflows/build-docs.yml94-99
3. Uploads artifacts for deployment .github/workflows/build-docs.yml100-104

Sources: .github/workflows/build-docs.yml1-118

Publish Workflow

The .github/workflows/publish.yml workflow triggers on GitHub release creation:

PyPI Publishing Pipeline

Key features:

• Uses OIDC trusted publishing (no API tokens needed) .github/workflows/publish.yml12
• Single command build: uv build .github/workflows/publish.yml27
• Single command publish: uv publish .github/workflows/publish.yml29

Sources: .github/workflows/publish.yml1-30

Deploy Documentation Workflow

The .github/workflows/deploy-docs.yml workflow deploys to Cloudflare Pages after documentation builds complete:

Documentation Deployment Flow

The workflow:

1. Sets deployment status to pending .github/workflows/deploy-docs.yml37-43
2. Downloads all language artifacts .github/workflows/deploy-docs.yml48-54
3. Deploys to Cloudflare Pages .github/workflows/deploy-docs.yml55-66
4. Comments deployment URL on PR .github/workflows/deploy-docs.yml75-82

Sources: .github/workflows/deploy-docs.yml1-83

Community Automation Workflows

FastAPI includes several scheduled workflows for community data management:

Workflow	Schedule	Purpose	Script
people.yml	Monthly (1st, 14:00 UTC)	Update expert lists	scripts/people.py
contributors.yml	Monthly (1st, 03:00 UTC)	Update contributor data	scripts/contributors.py
sponsors.yml	Monthly (1st, 06:00 UTC)	Update sponsor information	scripts/sponsors.py
topic-repos.yml	Monthly (1st, 12:00 UTC)	Update related projects	scripts/topic_repos.py
label-approved.yml	Daily (12:00 UTC)	Auto-label approved PRs	scripts/label_approved.py
notify-translations.yml	On PR label/close	Notify translation reviewers	scripts/notify_translations.py
latest-changes.yml	On PR merge	Update release notes	External action

Sources: .github/workflows/people.yml4-5 .github/workflows/contributors.yml4-5 .github/workflows/sponsors.yml4-5 .github/workflows/topic-repos.yml4-5 .github/workflows/label-approved.yml4-5 .github/workflows/notify-translations.yml3-6 .github/workflows/latest-changes.yml3-8

Coverage Reporting

The .github/workflows/smokeshow.yml workflow publishes coverage reports:

Smokeshow Coverage Reporting

Features:

• Automatic retry (up to 5 attempts) .github/workflows/smokeshow.yml40-47
• GitHub status check integration .github/workflows/smokeshow.yml49-51
• 100% coverage threshold .github/workflows/smokeshow.yml50

Sources: .github/workflows/smokeshow.yml1-55

Development Tools and Configuration

Code Quality Tools

FastAPI enforces code quality through multiple tools configured in pyproject.toml:

mypy Configuration

Type checking with strict mode enabled:

Overrides for specific modules:

• fastapi.concurrency: Relaxed import checking pyproject.toml211-214
• fastapi.tests.*: Allow untyped defs pyproject.toml216-219
• docs_src.*: Allow incomplete definitions pyproject.toml221-225

Sources: pyproject.toml207-225

pytest Configuration

Test execution settings:

Sources: pyproject.toml227-238

coverage Configuration

Coverage measurement and reporting:

Setting	Value	Purpose
parallel	true	Allow parallel test execution
data_file	coverage/.coverage	Coverage data location
source	["docs_src", "tests", "fastapi"]	Measured packages
relative_files	true	Portable paths
omit	Multiple patterns	Exclude test files, benchmarks

Sources: pyproject.toml240-261

ruff Configuration

Linting with multiple rule sets:

Per-file ignores defined for 50+ documentation example files pyproject.toml287-329

Sources: pyproject.toml270-336

Environment Configuration

FastAPI uses a .python-version file to specify the default Python version for development and CI:

• Python 3.13 is the current default
• Used by uv and GitHub Actions via python-version-file parameter

Sources: .github/workflows/test.yml168 .github/workflows/build-docs.yml49

Build Configuration

The pdm-backend build system includes source files in distributions:

Sources: pyproject.toml198-205

Environment Variables

The CI/CD system uses several environment variables for configuration:

Variable	Usage	Example Workflows
UV_NO_SYNC	Disable automatic sync	test.yml
UV_PYTHON	Target Python version	test.yml
UV_RESOLUTION	Dependency resolution strategy	test.yml
STARLETTE_SRC	Starlette installation source	test.yml
GITHUB_TOKEN	GitHub API authentication	All workflows
CLOUDFLARE_API_TOKEN	Cloudflare deployment	deploy-docs.yml
SMOKESHOW_AUTH_KEY	Coverage upload	smokeshow.yml

Sources: .github/workflows/test.yml15-17 .github/workflows/test.yml82-85 .github/workflows/deploy-docs.yml64 .github/workflows/smokeshow.yml54

Related Pages

• Package Configuration and Dependencies - Detailed pyproject.toml structure
• Dependency Management with uv - uv commands and lock file management
• CI/CD Pipeline - In-depth workflow documentation
• Development Workflow - Local development setup and practices
• Code Quality and Pre-commit Hooks - Quality enforcement tools
• Test Framework and Coverage - Testing infrastructure