How to Get Cookies in FastAPI: Simple Guide with Examples

In FastAPI, you get cookies by using the Cookie parameter from fastapi. Declare a function parameter with Cookie and FastAPI will extract the cookie value from the request automatically.

Syntax

Use the Cookie function from fastapi to declare a cookie parameter in your path operation function. FastAPI reads the cookie value from the incoming request and passes it to your function.

• cookie_name: str = Cookie(default_value) declares a cookie named cookie_name.
• If the cookie is missing, default_value is used or None if omitted.

python

from fastapi import FastAPI, Cookie

app = FastAPI()

@app.get("/items/")
async def read_cookie(my_cookie: str | None = Cookie(None)):
    return {"my_cookie": my_cookie}

Example

This example shows a FastAPI app that reads a cookie named token. If the cookie is present, it returns its value; otherwise, it returns null.

python

from fastapi import FastAPI, Cookie
from fastapi.responses import JSONResponse

app = FastAPI()

@app.get("/show-token")
async def show_token(token: str | None = Cookie(None)):
    if token:
        return {"token": token}
    return JSONResponse(content={"error": "No token cookie found"}, status_code=404)

Output

GET /show-token with cookie 'token=abc123' returns {"token": "abc123"}
GET /show-token without cookie returns {"error": "No token cookie found"} with 404 status

Common Pitfalls

1. Forgetting to import Cookie from fastapi. Without this import, your code will fail.

2. Using the wrong parameter type. The cookie parameter must be declared with Cookie, not as a normal function argument.

3. Not handling missing cookies. Always provide a default value like None to avoid errors when the cookie is absent.

python

from fastapi import FastAPI

app = FastAPI()

# Wrong: cookie parameter without Cookie()
@app.get("/wrong")
async def wrong(cookie_value: str):
    return {"cookie": cookie_value}

# Correct way
from fastapi import Cookie

@app.get("/right")
async def right(cookie_value: str | None = Cookie(None)):
    return {"cookie": cookie_value}

Quick Reference

Remember these tips when working with cookies in FastAPI:

• Import Cookie from fastapi.
• Declare cookie parameters with Cookie(default).
• Use None as default to handle missing cookies gracefully.
• Cookies are strings; convert if needed.

Key Takeaways

Use the Cookie parameter from fastapi to read cookies in your endpoint functions.

Always import Cookie from fastapi before using it.

Provide a default value like None to handle missing cookies safely.

Cookies are passed as strings; convert them if you need other types.

Avoid declaring cookie parameters as normal function arguments without Cookie().