What is a 404 error?
A 404 error is a message from the server indicating that it cannot find the page or file you tried to access. It is sent via the HTTP protocol, which governs communication between your browser and the web server. When the address doesn’t match an existing resource, the server returns the 404 status code along with an error page. You’ve probably seen messages like “404 Not Found” or “Page Not Found.”
In practice, this error occurs when a page has been deleted, moved without a redirect, or when the URL is misspelled. It can also happen if an internal link points to an outdated filename or if an element (such as a CSS file or an image) is no longer on the server. Unlike a 200 code, which confirms successful delivery, a 404 means that the resource does not exist—yet. For search engines, this means that the page should not be indexed as a general rule.
How do 404 errors work?
When you enter a web address, your browser sends an HTTP request to the web server. The server then searches for the content at the requested location. If the server cannot find it, it responds with an HTTP 404. This is, therefore, the result of a completely normal process in web communication, albeit with a negative outcome.
You can compare it to sending a letter to an address where the recipient no longer lives. The letter is returned, and you’re told that the address doesn’t exist—just like the browser does with a 404 error.
On most websites, 404 pages are customized with a logo, navigation, and perhaps a search function, so the user isn’t left completely lost. From a digital design perspective, you can use this page to reflect your brand and help the user find their way—perhaps even adding a touch of personality through tone or visual humor, if it fits the brand.
Why Do You Need to Know About 404 Errors?
You should be aware of 404 errors because they affect both the user experience and SEO. When a user lands on a dead page, they often get frustrated and leave the site—and that can quickly increase your bounce rate. At the same time, crawlers waste time on pages with no value, which reduces the efficiency of your crawl budget. This means that more important pages may not be visited and indexed as often.
Errors that aren’t handled can also create duplicate content if pages with no content return a 200 status code instead of a 404. This is called a “soft 404” and can confuse Google’s algorithms. Proper status code handling is therefore part of technical SEO and an important element when developing a site optimization strategy—for both users and search engines.
What types and varieties are available?
- Standard 404 – a classic “not found” error, where the server returns status code 404 without further explanation. It may be temporary if the page simply lacks a redirect.
- Soft 404 – the page does not exist, but incorrectly returns a 200 OK status code. This causes the crawler to believe that the page is still valid.
- Related status codes – 410 Gone means the page has been permanently removed. 301 and 302 are used for redirects, while 403 means access has been denied. When working with SEO, it’s important to choose the right code so that search engines interpret your signal correctly.
How do you handle 404 errors in practice?
Effective management starts with regular monitoring. You can use Google Search Console to find errors such as “Submitted URL not found (404).” Other tools like Ahrefs, SEMrush, or Moz can crawl your site and identify broken links. This way, you can quickly identify where the problem lies—whether it’s internal links, incorrect sitemap URLs, or external links pointing to pages that no longer exist.
Once you’ve identified the errors, you should correct them based on the cause. If a page has been moved, set up a 301 redirect to the new location. If it has been permanently deleted without a replacement, let it return a 404 or 410. This is where SEO and strategy intersect—you need to decide whether the page still has value worth preserving or if it can be removed entirely.
In addition, you should review your internal links on an ongoing basis. An editorial workflow for content updates can ensure that old articles don’t link to pages that no longer exist. If you’re working on larger content projects or using automated processes in your CMS, good technical collaboration between web development and digital marketing helps prevent errors right from the start of the publishing process.
A good place to start is the following check:
- Check Search Console for new 404 errors at least once a month
- Update internal links when you move or delete pages
- Set up redirects at the server or CMS level—not through scripts
- Keep the sitemap.xml file up to date and resubmit it after making changes
- Design the 404 page with clear navigation elements so that the user can continue
What should you keep in mind?
404 errors may seem harmless, but their cumulative effect can be significant, especially on large websites. That’s why you shouldn’t just react when you discover them—you need to prevent them. Make sure your CMS generates correct status codes and that redirects don’t create loops or send traffic to irrelevant pages.
When working with SEO and content, it’s also important to decide when to remove pages entirely and when to keep them with updated content. A consistent structure with clear categories and stable URLs reduces the risk of broken links. This way, you improve both the user experience and your website’s technical health.
