Learn FASTAPI with Real Code Examples

FastAPI is designed for building RESTful APIs quickly and efficiently using Python.

Supports Python type hints for automatic validation and documentation generation.

Integrates with Pydantic for data validation and serialization.

Includes automatic interactive API docs using Swagger UI and ReDoc.

Well-suited for modern backend applications, microservices, and asynchronous APIs.

Route handling with type-checked parameters

Data serialization/deserialization via Pydantic

Built-in support for OAuth2, JWT, and authentication

Dependency injection for reusable components

Asynchronous request handling for scalability

FastAPI app – core application instance

Routes – endpoints with automatic parameter validation

Pydantic models – data validation and serialization

Dependencies – reusable injected logic

Middleware – functions applied to requests/responses

main.py - entry point

routers/ - route modules

models/ - Pydantic models for data

dependencies/ - reusable dependencies

services/ - business logic and integrations

Create FastAPI app with `FastAPI()`

Define routes with decorators (`@app.get/post`) and Pydantic models

Add dependencies for modular logic

Register routers for modular project structure

Start server with `uvicorn main:app --reload`

Beginner: simple GET/POST endpoints

Intermediate: CRUD APIs with models

Advanced: async DB integration and OAuth2

Expert: complex microservices with background tasks

Auditor: optimize performance and validation schemas

FastAPI vs Flask: FastAPI is async-first with type hints; Flask is synchronous and lightweight

FastAPI vs Django REST Framework: FastAPI is async and high-performance; DRF is more opinionated and full-featured

FastAPI vs Tornado: FastAPI provides modern type hints and automatic docs; Tornado focuses on async I/O

FastAPI vs Falcon: Falcon is minimalist; FastAPI adds validation and docs

FastAPI vs Express: Python ecosystem vs Node.js ecosystem

2018 – FastAPI initial release

2019 – Async support with Starlette

2020 – Dependency injection and security enhancements

2021–2022 – Performance optimizations and community growth

2023–2025 – Expanded ecosystem, async DB and caching integrations

FastAPI app - core application instance

Route - HTTP endpoint with type hints

Pydantic model - data validation and serialization

Dependency - reusable logic injected into routes

Middleware - function processing requests/responses