All posts
Networking3 min readWatchFor Team

404 Not Found: what it means and how to handle it

404 is the internet's most famous error — and unlike most, it's often nobody's emergency. Here's what it means, when it's fine, when it isn't, and how to handle it well.

404 Not Found: what it means and how to handle it

You click a link and land on it: 404 Not Found. It's the most recognised error on the web — so common it's become a meme. But behind the joke is a useful, specific message, and how you handle 404s says a lot about the quality of your site.

What a 404 actually means

A 404 is a client error (4xx) that means exactly one thing: the server is fine, but the thing you asked for doesn't exist here. The URL is wrong, the page was moved or deleted, or it never existed.

404 is not a server failure. Unlike a 500 or 502, nothing is broken — the server answered correctly. It's saying "that address has no page," not "I crashed."

When a 404 is fine (and when it's not)

SituationVerdict
Someone typo'd a URL✅ Totally normal
An old, intentionally-removed page✅ Fine (consider a redirect)
A page you deleted that still has inbound links⚠️ Fix with a redirect
A link inside your own site returns 404❌ A broken link — fix it
A page that should exist but 404s❌ A real bug

The first two are healthy. The last three are the ones worth hunting down — especially broken internal links, which frustrate users and hurt SEO.

Make a helpful 404 page

A default 404 is a dead end. A good one keeps people on your site:

  • A clear, human message ("This page doesn't exist") — not a stack trace.
  • A search box and links to popular pages.
  • Your navigation so visitors can carry on.
  • Matching your site's design, so it doesn't feel like an error from another planet.

404 vs 410 — a subtle SEO point

If a page is gone permanently and never coming back, 410 Gone tells search engines exactly that, so they drop it faster. A 404 says "not found right now" (might return); 410 says "deliberately gone." For most cases 404 is fine, but 410 is the cleaner signal for intentional removals.

The SEO angle

Search engines expect some 404s — they're normal. What hurts is:

  • Internal links pointing to 404s (wastes crawl budget, frustrates users).
  • Deleted pages that had traffic/backlinks returning a bare 404 instead of a 301 redirect to a relevant replacement.

So: let genuine "not found" be a 404, but redirect removed pages that people still reach.

How to catch the bad ones

You don't want to prevent all 404s — you want to catch the ones that matter: broken internal links and pages that should exist. Monitoring helps by watching your key URLs and alerting if a page that should return 200 suddenly returns 404 — turning a silent broken page into something you fix in minutes.

The bottom line

In one line
WhatThe page doesn't exist — the server is fine.
Normal?Yes, for typos and old URLs.
FixBroken internal links; redirect removed pages with traffic.
PolishA helpful 404 page with search and navigation.

A 404 isn't something to fear — it's something to handle gracefully. Make the page helpful, redirect what deserves it, and monitor the URLs that should never 404.

More codes in HTTP status codes explained; watch your key pages with web monitoring.

Share this article