A fully working REST API with GET, POST, PUT, and DELETE endpoints — complete with automatic interactive documentation at /docs.
FastAPI is the framework. Uvicorn is the server that runs it.
pip install fastapi uvicornCreate a file called main.py and add a basic GET route. FastAPI reads your type hints to validate data automatically.
# main.py
from fastapi import FastAPI
app = FastAPI()
@app.get("/")
def read_root():
return {"message": "Hello from FastAPI!"}
@app.get("/items/{item_id}")
def read_item(item_id: int, q: str = None):
return {"item_id": item_id, "query": q}Start the server, then open your browser. FastAPI auto-generates interactive docs.
uvicorn main:app --reloadINFO: Uvicorn running on http://127.0.0.1:8000 INFO: Started reloader process INFO: Application startup complete.
Use Pydantic models to define the shape of incoming data. FastAPI validates it automatically and returns clear error messages if the data is wrong.
from fastapi import FastAPI
from pydantic import BaseModel
from typing import Optional
app = FastAPI()
# In-memory store (use a database in production)
items = {}
class Item(BaseModel):
name: str
price: float
in_stock: bool = True
description: Optional[str] = None
@app.get("/items")
def list_items():
return items
@app.post("/items/{item_id}")
def create_item(item_id: int, item: Item):
items[item_id] = item
return {"message": "Created", "item": item}Complete the CRUD API with update and delete endpoints.
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from typing import Optional
app = FastAPI()
items = {}
class Item(BaseModel):
name: str
price: float
in_stock: bool = True
description: Optional[str] = None
@app.get("/items")
def list_items():
return items
@app.get("/items/{item_id}")
def get_item(item_id: int):
if item_id not in items:
raise HTTPException(status_code=404, detail="Item not found")
return items[item_id]
@app.post("/items/{item_id}")
def create_item(item_id: int, item: Item):
items[item_id] = item
return {"message": "Created", "item": item}
@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):
if item_id not in items:
raise HTTPException(status_code=404, detail="Item not found")
items[item_id] = item
return {"message": "Updated", "item": item}
@app.delete("/items/{item_id}")
def delete_item(item_id: int):
if item_id not in items:
raise HTTPException(status_code=404, detail="Item not found")
del items[item_id]
return {"message": "Deleted"}# POST /items/1 with body: {"name": "Laptop", "price": 999.99}
{"message": "Created", "item": {"name": "Laptop", "price": 999.99, "in_stock": true, "description": null}}
# GET /items/1
{"name": "Laptop", "price": 999.99, "in_stock": true, "description": null}
# DELETE /items/1
{"message": "Deleted"}You built a full CRUD REST API with automatic validation and interactive documentation. FastAPI is one of the fastest Python frameworks — and the /docs page alone makes it worth learning.
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