How to Redirect in FastAPI: Simple Guide with Examples

In FastAPI, you can redirect a client to another URL by returning a RedirectResponse from fastapi.responses. Use RedirectResponse(url="target_url") inside your path operation function to send a redirect response.

Syntax

To redirect in FastAPI, import RedirectResponse from fastapi.responses. Then return RedirectResponse with the target URL as the url parameter.

• RedirectResponse(url="target_url"): Creates a redirect response to the given URL.
• The default HTTP status code is 307 (Temporary Redirect), but you can specify others like 301 (Permanent Redirect) using the status_code parameter.

python

from fastapi.responses import RedirectResponse

# Redirect to another URL
return RedirectResponse(url="/new-path", status_code=307)

Example

This example shows a FastAPI app with a root path that redirects the user to the /welcome path using RedirectResponse. When you visit /, the browser will be redirected to /welcome.

python

from fastapi import FastAPI
from fastapi.responses import RedirectResponse

app = FastAPI()

@app.get("/")
async def root_redirect():
    return RedirectResponse(url="/welcome")

@app.get("/welcome")
async def welcome():
    return {"message": "Welcome to the redirected page!"}

Output

Visiting '/' redirects to '/welcome' and shows JSON: {"message": "Welcome to the redirected page!"}

Common Pitfalls

• Forgetting to import RedirectResponse causes errors.
• Not returning the RedirectResponse object (e.g., just calling it without return) means no redirect happens.
• Using the wrong status code can confuse browsers; 307 is recommended for temporary redirects.
• Redirecting to external URLs requires full URLs starting with http:// or https://.

python

from fastapi.responses import RedirectResponse

# Wrong: missing return
@app.get("/wrong")
async def wrong_redirect():
    RedirectResponse(url="/welcome")  # This does NOT redirect

# Correct:
@app.get("/correct")
async def correct_redirect():
    return RedirectResponse(url="/welcome")

Quick Reference

Action	Code Example	Notes
Redirect to internal path	return RedirectResponse(url="/path")	Default status code 307 (temporary)
Redirect with permanent status	return RedirectResponse(url="/path", status_code=301)	301 means permanent redirect
Redirect to external URL	return RedirectResponse(url="https://example.com")	Use full URL with scheme
Forget to return redirect	RedirectResponse(url="/path")	No redirect happens without return

Key Takeaways

Use RedirectResponse from fastapi.responses to perform redirects.

Always return RedirectResponse from your path operation function.

Default redirect status code is 307; specify status_code for others like 301.

Redirect URLs can be internal paths or full external URLs.

Common mistake: forgetting to return the RedirectResponse object.