Django Messages Not Showing After Redirect: Debug Trap with messages.get_messages Explained

Fix Django messages not showing after redirect. Learn how messages.get_messages consumes the queue and why login errors vanish, plus the quick fix that works.

Django messages not showing up after a redirect can be infuriating, especially when everything else looks correct. If your login view calls messages.error on invalid credentials but the alert never appears on the login page, there’s a subtle trap that can wipe out the message before the template ever sees it.

Symptom

After submitting wrong credentials, the app redirects back to the login screen, but the expected error banner is missing. Server logs show a normal flow with POST returning 302 and then a GET of the login page.

Problematic code example

The issue hides in the view logic that inspects the message queue during debugging. Even though the messages framework and template setup are fine, a single line forces Django to clear the message storage prematurely.

from django.shortcuts import render, redirect
from django.contrib.auth import authenticate, login
from django.contrib import messages
import logging
def auth_view(req):
    logging.debug(f"Method: {req.method}")
    if req.method == 'POST':
        uname = req.POST['username']
        pwd = req.POST['password']
        logging.debug(f"BODY: {req.POST}")
        acct = authenticate(req, username=uname, password=pwd)
        if acct is not None:
            login(req, acct)
            logging.debug("OK: authenticated, redirecting to home")
            return redirect('home')
        else:
            messages.error(req, "Invalid username or password. Please try again.")
            logging.debug("FAIL: invalid credentials, flagging error")
            logging.debug(f"Messages: {list(messages.get_messages(req))}")
            return redirect('login')
    else:
        logging.debug("Render login page")
        return render(req, "registration/login.html", {})

Why this happens

The messages.get_messages(request) call reads from the message storage and consumes its contents. That behavior is by design, so messages are displayed once and then cleared. When that call runs inside the view for debugging, it removes the queued error before the redirect completes. The template then renders with an empty messages collection.

Fix

Remove the code that drains the message storage. Keep setting messages.error and redirecting as before. The message will survive the redirect and be available to the template.

from django.shortcuts import render, redirect
from django.contrib.auth import authenticate, login
from django.contrib import messages
import logging
def auth_view(req):
    logging.debug(f"Method: {req.method}")
    if req.method == 'POST':
        uname = req.POST['username']
        pwd = req.POST['password']
        logging.debug(f"BODY: {req.POST}")
        acct = authenticate(req, username=uname, password=pwd)
        if acct is not None:
            login(req, acct)
            logging.debug("OK: authenticated, redirecting to home")
            return redirect('home')
        else:
            messages.error(req, "Invalid username or password. Please try again.")
            logging.debug("FAIL: invalid credentials, flagging error")
            return redirect('login')
    else:
        logging.debug("Render login page")
        return render(req, "registration/login.html", {})

Why this matters

Debug statements that touch stateful APIs can change application behavior in non-obvious ways. Django’s messages framework follows a single-consumption model, so reading the queue as part of a log statement effectively erases the very data you expect to render later. Understanding this prevents hours of chasing non-issues in templates or URL routing.

Takeaways

If a message set before a redirect doesn’t appear, verify you aren’t iterating over or accessing the message queue in the view. Set the message, redirect, and let the template consume it. That simple change restores the expected flow and keeps your login UX consistent.