What is 404 Error?
404 Error is an HTTP response status indicating that a web server can't find the resource requested at a particular URL. The requested page may have been deleted, moved, renamed, or entered incorrectly. A 404 response doesn't necessarily mean the entire website is unavailable, because other URLs can continue working normally.
Quick Facts About 404 Error
Category
HTTP status code
Used for
Reporting a missing web resource
Relevant standard
HTTP Semantics, RFC 9110
Common confusion
A missing page is not the same as an unavailable website
Also called
404 Not Found, HTTP 404
Often discussed with
SEO Audits, Technical SEO
Key Takeaways About 404 Error
- A 404 response means the requested URL cannot be matched to an available resource.
- Deleted or moved pages can create 404 responses when redirects are not configured.
- A helpful 404 page should explain the problem and guide visitors towards relevant content.
- Large numbers of important 404 responses can waste crawl activity and harm user experience.
- A 301 redirect is usually better when a suitable replacement page exists.
Understanding 404 Error
404 Error is an HTTP status code. A web server returns it when it can't find a requested URL resource. The resource may be a webpage, image, document, or other file. The server is reachable, but the location has no available resource.
Related glossary terms: 301 Redirect, Crawlability, Crawl Budget.
A missing resource can result from a deleted page, changed URL, typing error, or outdated link. A 404 response doesn't mean an entire website is offline. Other pages may load normally. One specific address may remain unavailable.
How 404 Error Works, Is Measured, or Is Used?
When a browser or search crawler requests a URL, the server returns an HTTP response status. It may also return a custom error page. A genuine 404 response tells the system that the resource wasn't found. The response can include helpful navigation, a search function, or relevant links. These additions don't change the status code.
Website owners usually identify 404 responses through server logs, Google Search Console, website crawlers, analytics reports, and browser testing. Each finding should be assessed instead of fixed automatically. A broken internal link needs correction. A permanently moved page may need a 301 redirect. An invalid address may correctly remain a 404.
Search engines distinguish an ordinary 404 from a soft 404. A soft 404 occurs when a page appears to return successful content. It often has a 200 status. The page tells visitors that the requested item is missing. Clear status codes help crawlers understand the website. They also reduce confusion during indexing.
Why 404 Error Matters?
404 responses matter because they affect user experience and technical SEO. Visitors may leave after finding repeated missing pages. They may leave before finding information, completing an enquiry, or buying a product. Search crawlers can also request broken URLs instead of useful pages. This matters on large or frequently changing websites.
Not every 404 is harmful. Some are expected, including mistyped addresses, expired campaign URLs, and malicious requests. These requests may target files that never existed. The practical risk comes from important URLs, valuable backlinks, or heavily visited pages. The risk grows when no suitable alternative exists. Reviewing context prevents unnecessary redirects. It also preserves a clear site structure.
When 404 Error Matters Most?
404 errors deserve prompt attention after a website migration, domain change, or navigation redesign. They also matter after a product catalogue update. They're important when a high-value page has external links or strong search visibility. They're also important when it supports a conversion journey. A relevant redirect can preserve access. It can also help transfer established signals to the replacement URL.
Regular monitoring helps ecommerce websites, local service websites, publishers, and large organisations. These sites often have many URLs. A useful review groups errors by source, visits, backlinks, and business importance. The right response may repair an internal link, restore content, or redirect to a close replacement. A 404 may stay when no equivalent resource exists.
How to Evaluate 404 Error?
- Check whether important URLs return 404 responses in server logs, Google Search Console, and crawler reports.
- Confirm that internal links do not point to deleted, renamed, or incorrectly typed URLs.
- Review referral traffic and backlinks before removing a page or choosing a redirect destination.
- Test whether the custom 404 page provides clear navigation, search, and a route back to relevant content.
- Compare genuine 404 responses with soft 404 pages that incorrectly return successful status codes.
Related Concepts Compared
404 Error vs. 301 Redirect
A 301 redirect sends visitors and crawlers to a different, permanent URL. A 404 Error states that the requested resource cannot be found and does not provide a replacement destination.
404 Error vs. Soft 404
A soft 404 looks like a missing-page message but usually returns a successful HTTP status, such as 200. A genuine 404 uses the appropriate not-found status.
404 Error vs. 500 Internal Server Error
A 500 error indicates an unexpected problem on the server while processing a request. A 404 generally means the server worked but could not locate the requested resource.
Expert Note
Do not redirect every 404 to the homepage. A redirect is most useful when the replacement page closely matches the original intent. Otherwise, keeping a clear 404 response avoids misleading visitors and search engines.
Common Mistakes or Myths About 404 Error
- Redirecting every missing URL to the homepage, regardless of content relevance.
- Returning a 200 status for a page that clearly says the requested content is missing.
- Ignoring broken internal links because the website homepage still loads.
- Removing a page without checking its search traffic, backlinks, or role in navigation.
- Treating crawler requests for nonexistent or malicious URLs as genuine website failures.
404 Error in Practice: A Real-World Example
A retailer removes an old blue jacket page but leaves product links and search results pointing to its former URL. Visitors receive a 404 Error. The retailer can restore the page, redirect it to a closely related replacement, or retain the 404 if no equivalent product exists.
Sources & Further Reading on 404 Error
- RFC 9110: HTTP Semantics, Section 15.5.5, 404 Not Found
- Google Search Central: Soft 404 errors
- MDN Web Docs: 404 Not Found
Related Services
Related Terms
301 Redirect
301 Redirect is a permanent server instruction that sends users and search engines from one URL…
Crawlability
Crawlability is the ability of search engine crawlers to access, discover, and retrieve pages, files, and…
Crawl Budget
Crawl Budget is the number of URLs a search engine crawler chooses to request from a…
Indexability
Indexability is a webpage’s ability to be discovered, processed, and stored in a search engine’s index…
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