Find & Fix 404 Errors

A 404 error means a visitor or crawler requested a URL that no longer exists on your site. To fix 404s in WordPress with Hydrogen SEO: find them (through the 404 Monitor, Google Search Console and Hydrogen SEO's site audit), decide whether each URL deserves a redirect or should stay dead, and create 301 redirects in the Redirection Manager for the ones worth saving. No .htaccess editing is involved.

Each source sees a different slice. Search Console shows what Googlebot found, the site audit shows broken links inside your own content, and the 404 Monitor (version 0.0.27 and later) shows what real visitors and bots are actually requesting. Fixing happens in the Redirection Manager, which the 404 Monitor can hand a URL to directly.

Not every 404 is a problem, and not every 404 should be redirected. This guide walks through where 404s come from, how to find the ones that matter, and how to fix them properly.

Where 404s come from

Most 404s trace back to a handful of causes:

• Renamed slugs. You edit a post's permalink from /seo-tips/ to /wordpress-seo-checklist/ and WordPress does not always leave a redirect behind. Every existing link to the old slug now breaks.
• Deleted posts and pages. Content gets trashed during a cleanup, but internal links, backlinks, and search results still point at it.
• Inbound typos and bad external links. Another site links to /prcing/ instead of /pricing/, or truncates your URL. You never created the broken URL, but visitors are hitting it anyway.
• Site restructures and migrations. New permalink structures, category changes, or a domain move orphan every old address at once.
• Old media and attachment URLs. Images and files removed from the media library keep receiving requests from pages that embedded them.

Find your 404s

1. Google Search Console

1. Open Search Console and go to Indexing → Pages.
2. Under "Why pages aren't indexed", look for Not found (404).
3. Open the report and export the list of URLs. These are 404s Google itself has crawled, which makes them the highest-priority list: each one is a URL Google knew about, often because something links to it.

Also check Links → Top linked pages for any URL earning backlinks that now returns a 404. Those are the most expensive dead ends on your site.

2. Hydrogen SEO's site audit

The site-wide audit crawls your own content and reports broken internal links: places where one of your pages links to a URL on your site that returns a 404. These are entirely under your control and should be fixed first, because you are actively sending both visitors and crawlers into dead ends.

1. Go to Hydrogen SEO → Dashboard and run a site audit.
2. Open the Broken internal links results.
3. For each entry, note the broken target URL and the page linking to it.

3. The 404 Monitor

Switch on Hydrogen SEO → 404 Monitor (under Tools) and it records every front-end request that ends in a 404, grouped by URL, with a hit count, first and last seen dates, the last referrer and the last user agent. It catches what the other two cannot: inbound typos on other sites, old newsletter links, hotlinked images that were deleted. No IP addresses are stored.

Sort it by hits to find the broken URLs that cost the most visits, and check the last referrer: when it is one of your own pages, the fix is editing that link. Rows can be turned into a redirect directly. The details are in the 404 Monitor.

4. Server logs

Your host's access logs record every request, including 404s for static files the web server answers without loading WordPress, which the monitor never sees. They are worth a look when you are chasing missing images or downloads.

Fix them

For each 404, choose one of three outcomes:

Redirect it (most common). If a replacement or closely related page exists, create a 301:

1. Go to Hydrogen SEO → Redirections.
2. Click Add Redirect.
3. Source: the dead path (for example /old-guide/). Target: the best replacement page.
4. Choose 301 (Permanent) and save.

curl -I before: /old-coffee-guide returns 404 Not Found.

Redirect to the most relevant page, not the homepage. If you are unsure whether a move deserves a 301 or 302, the 301 vs 302 guide has a decision table.

Fix the link at its source. For broken internal links, the cleaner fix is often editing the linking page so it points to the correct URL directly. A redirect papers over the problem; updating the link removes it. Do both when the broken URL also has external links.

Leave it as a 404 (or send a 410). If the content is gone for good and nothing on your site replaces it, a 404 is the correct, honest response. Redirecting unrelated dead URLs to your homepage tends to be treated as a soft 404 by Google anyway. A 410 ("Gone") is a slightly stronger hint that removal was deliberate, which can get URLs dropped from the index a little faster; for most sites, a plain 404 is perfectly fine.

Prevent the next batch

• When you rename a slug, add the 301 in the same sitting.
• When you delete a post, decide its redirect (or deliberate 404) as part of deleting it.
• Re-run the site audit after content restructures, and keep your XML sitemap current so crawlers focus on URLs that exist.
• Recheck Search Console's 404 report monthly, and glance at the 404 Monitor sorted by last seen after any launch or migration; a URL that suddenly collects hits is the earliest warning that something broke.

FAQ

Are 404s bad for SEO?

A 404 on a URL that never mattered is harmless; Google expects sites to have them. The damage comes from 404s on URLs with backlinks, internal links, or traffic: those waste link value and lose visitors. Fix the ones that matter, and do not chase a "zero 404s" vanity metric.

Should I redirect every 404 to my homepage?

No. Google typically treats mass redirects to an irrelevant page as soft 404s, and visitors do not get what they came for. Redirect to the closest relevant page, or let the URL 404 honestly.

What is the difference between a 404 and a 410?

404 says "not found"; 410 says "gone, deliberately removed". Search engines may drop 410 URLs slightly faster. Functionally, for most WordPress sites, the difference is minor.

How do I find which page contains a broken internal link?

Hydrogen SEO's site audit lists the linking page alongside each broken target, so you can jump straight to the page that needs its link edited.

Related reading

• The 404 Monitor
• The Redirection Manager
• 301 vs 302 redirects
• Site-wide audits
• XML sitemaps
• The complete guide to redirects