What is the difference between Flask, Django, and FastAPI?

Flask, Django, and FastAPI are popular Python frameworks for web development, but they differ in approach and capabilities:

• Flask is a minimalist microframework. It provides a basic set for creating web applications without built-in ORM, forms, or authentication. It allows flexible component selection. Good for small projects and when maximum customization is needed.

• Django is a full-featured framework with a "batteries included" approach, offering a large set of tools: ORM, authentication system, admin panel, routing, templates. Suitable for large projects where development speed and standardization are important.

• FastAPI is a modern asynchronous framework focused on high performance and ease of API development. Uses Python typing for auto-generation of documentation (Swagger), data validation, and async/await support. Ideal for microservices and high-load APIs.

Example of a simple API in FastAPI:

from fastapi import FastAPI

app = FastAPI()

@app.get("/items/{item_id}")
async def read_item(item_id: int):
    return {"item_id": item_id}

The choice depends on the task: if you need a simple site — Flask; if a large project with many features — Django; if a fast and modern API — FastAPI.