303 Status Code: 3 Easy ways to fix it

Troubleshooting a 303 status code on your website? This temporary redirect gets triggered after submitting forms to ensure data isn’t re-submitted if a user refreshes the page. However, incorrect implementation of this HTTP response status code can lead to issues like form data duplication, web navigation errors, or slower page loading.

In this guide, we’ll explore the 303 status code, its proper use, and potential problems. We’ll also show you 3 ways to fix and optimize it for a smoother web experience.

That is typically a POST request submitted by the user to the original target resource. The 303 status code is defined in RFC 7231 Section 6.4.4 as “See Other.”

Like other 3XX HTTP status codes, 303 is considered a temporary redirect but requires a GET method to retrieve the requested resource.

However, using a 303 HTTP status code can become problematic in certain scenarios. If not done right, it may cause caching issues, increased bandwidth usage, and slower loading times. That can compromise the overall user experience and satisfaction.

Moreover, outdated systems may not properly process 303 responses, leading to compatibility issues. Misconfiguration, like using 303 instead of 301 permanent and 302 temporary redirects, can also lead to incorrect navigation and request handling errors.

When & How is the 303 Status Code Used?

The 303 status code is used when a browser sends data to a server through an HTTP POST request. After successfully processing the request, the server responds with a 303 redirect instructing the browser to load a different URL using the GET method. This redirect prevents the browser from reloading the original page and inadvertently resubmitting the data.

You should not confuse 303 redirects with the 301 and 302 redirects, as they serve different purposes. Here is how they differ:

• 301 Moved Permanently – This redirect is used when a resource has been permanently moved. It tells clients and search engines to update their records, replacing the old URL with the new one in bookmarks and search indices.
• 302 Found is employed for temporary redirections. A 302 redirect does not specify how clients should re-request the resource, typically retaining the original request method (POST, GET, etc.).

Unlike 302, a 303 redirect specifically mandates using the GET method, which is ideal for scenarios like form submissions to prevent duplicate POST actions on refresh.

Technical Example of 303 Usage

To examine a more technical example of using the HTTP 303 status, we’ll take the case of a newsletter subscription page.

Let’s say you want to subscribe to a website’s newsletter. Below, we’ll outline how your action is processed and the result you see in this exact scenario.

Here is a more detailed description of the graphic shown above:

1. When you click “Submit” on the form, your browser sends an HTTP POST request to the web server software. This request usually contains the data you’ve entered into the form fields. Here is an example of a signup form’s custom code and the data it collects:

<form method="POST" action="/subscribe-newsletter">
<input type="email" name="email" required placeholder="Enter your email">
<button type="submit">Subscribe</button>
</form>

2. Then, the server processes the data sent with the POST request. It adds your email to the newsletter list.
3. Next, the server responds with an HTTP 303 status code and Location header pointing to the Confirmation page URL.

Here is a basic example of the server’s response codes sent to the browser.

HTTP/1.1 303 See Other
Location: https://www.example.com/thank-you.html

4. Upon receiving the 303 status response code, the browser immediately checks the Location header field to determine where to redirect you.
5. Regardless of the original method used (in this case, POST), the browser uses a GET method to fetch the resource URL specified in the Location header field. This prevents the original POST data from being resubmitted if the user happens to refresh the new web page.
6. Then, the browser navigates to the URL specified with the Location field value using a GET request. It also caches the requested web page to use for future requests
7. In the final logical step, the browser serves you a “Confirmation” page.

What Triggers an HTTP 303 Status Code?

The 303 response code is a result of a client’s request. It’s often misunderstood as an error, but it simply indicates that the server redirects you to a different location. That response indicates that the requested resource can be found at a new location and retrieved with a GET request, regardless of the original request method.

The 303 status code may be triggered by unintentional redirect instructions when mistakenly used instead of 301 or 302 redirects. Although the request’s primary location might still be the original target resource, the 303 redirect temporarily shifts the interaction to a new location URL.

The key here is that the 303 redirect is meant for the client to retrieve the result (or a related resource), NOT to indicate that the original resource has permanently moved or changed its primary URL.

Another cause of the 303 status may be an application’s custom code or server misconfiguration incorrectly handling HTTP methods, leading to the wrong execution of intended actions.

Potential issues related to the 303 HTTP Status Code

If the 303 redirect fails, you might encounter problems like the following:

• The browser may show a 404 Not Found error or fall into infinite redirection loops. It can also toss users onto the wrong pages, affecting both the user experience and the flow of the web application.
• Or increased bandwidth usage by the excessive data in exchange between user agents (server-client).
• And high server load because the server has to deal with unnecessary client requests.
• Also, some caching issues may arise if the target location in a 303 is not set with proper caching headers. Some clients and intermediate proxies might incorrectly cache the 303 response rather than the result of the subsequent GET request.
• Plus, if search engines get confused by the wrong pages, it might even affect your website’s SEO. Note that 303 redirects do not pass link equity. Thus, using them in situations better suited for 301 (permanent redirects) can lead to poor SEO outcomes.

So, it’s highly important to ensure these redirects are set up correctly to keep everything running smoothly and your users happy.

How to Fix an HTTP 303 Status Code (3 Ways)

If you are having trouble with a 303 redirect that doesn’t execute properly or causing other issues, this section will show you 3 ways to fix it.

Examine your Server Configuration and Logs

You must examine your server configuration to troubleshoot a problematic 303 status code. Fixing a 303 status code issue often involves understanding why your web hosting server (Apache or Nginx) sends these redirects inappropriately or excessively.

To address it, you can examine your server logs for clues on what might be triggering these responses. Here’s how you can proceed:

1. Access your server logs.
   For Apache, the logs are typically found in /var/log/apache2/ on Ubuntu or /var/log/httpd/ on CentOS. For Nginx, check in /var/log/nginx/. Inside these directories, look for error logs (like error.log) or access logs (like access.log). Keep in mind that most managed hosting providers restrict access to the server logs for the sake of security.

2. Analyze the log files.
   Open the log files and search for entries related to 303 status codes. You can use tools like grep for this purpose. For example:

grep “303” ~/www/yourdomain.com/logs/yourdomain.com-2024-05-*

3. Identify patterns in your logs findings. Look for any patterns or commonalities in the requests that are resulting in 303 responses. Key details to note include:
   • The URLs or endpoints being requested with the head request.
   • The time and frequency of these requests.
   • Any related actions or errors listed before or after the 303 entries.

4. Review your server configuration
   Based on your findings, review the .htaccess file for any misconfigurations or rules that might be causing the unintended 303 redirects. Look specifically for rewrite rules, redirection configurations, or proxy settings that could trigger the 303 status incorrectly. For example:

RewriteEngine On
RewriteRule ^oldpath$ /newpath [R=303]

5. Adjust your configuration

If you identify problematic rules or settings, modify them accordingly. This might involve changing the status code, adjusting the conditions under which the redirect occurs, or removing the rule entirely if it’s not needed.

6. Test the fix

Finally, verify that the issue is resolved by retesting the scenarios that previously led to the 303 redirects. Use tools like curl to simulate requests and observe the responses:

curl -I http://yourdomain.com/path

If the server logs didn’t give you any clues, keep reading to learn how to examine your application logs.

Check your Application Logs & Debug

If you are troubleshooting a 303 status in WordPress – start by digging into your application logs and settings:

1. Review your WordPress Logs for error messages or unusual entries related to the 303 status. This guide to WordPress logs will help you access detailed logs.
2. Enable WordPress’s Debug mode to boost your site’s transparency. Find the wp-config.php file in your root folder and edit it to change the following line from define (‘ WP_DEBUG’, false) to define (‘ WP_DEBUG’, true). Or add the following snippet:
   

   

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);

This code snippet enables WordPress debugging and logs errors to a file named debug.log in the wp-content directory. This way it keeps the error messages hidden from visitors, which is a good practice for maintaining site security and user experience.

3. Deactivate WordPress plugins to check if any plugin creates a conflict and causes unexpected HTTP statuses. Disable them temporarily to see if the issue resolves, then re-enable them one by one to identify the culprit.
   

   

Implementing these steps systematically will help you identify and correct the source of the 303 status, ensuring your WordPress site functions optimally.

If everything seems fine with your application configuration, you may need to check on your client-side calls, so read on for more information on this fix.

Update Client-side Calls

Sometimes, the problem lies with the client-side HTTP calls. Make sure that the calls to the server are correctly formatted and that the retrieval request method specified is appropriate for the action.

For instance, changing a POST to a GET in your AJAX calls might resolve the issue if the server is set to respond differently based on the request method.

Review the logic that handles redirection on the client side. It’s crucial that the client correctly interprets the 303 status and transitions from the original POST request to a GET request for the new URL. This often involves tweaking client-side scripts to ensure they don’t automatically retry the original request but instead follow the new URL specified in the 303 response.

Here is an example of an AJAX call :

fetch(url, {
method: 'POST',
body: data
})
.then(response => {
if (response.status === 303) {
return window.location = response.headers.get('Location');
}
return response.json();
})

.catch(error => console.error('Error:', error));

This snippet ensures that if the server responds with a 303 status code, the client will follow the redirect as intended.

Does a 303 Status Code Impact SEO Performance?

A 303 response code is primarily used after form submissions to prevent data resubmission on page refresh. As opposed to 301 or 302 redirects, which pass link equity to the new URL, a 303 is considered temporary and does not transfer SEO value, leaving the original URL’s ranking intact.

However, excessive use of 303 redirects can strain your site’s crawl budget and increase page load times, as each redirect introduces an extra loading step. Therefore, while 303 redirects enhance user experience by avoiding duplicate submissions, they should be used sparingly to prevent negative impacts on your site’s SEO performance.

Best Practices for 303 Redirects and SEO

Employ 303 redirects primarily for their intended purpose. This includes handling form submissions and method changes where putting the user back on the same URL could result in duplicate actions or incorrect HTTP method usage.

You should also monitor for and keep away from redirect chains. 303 redirects should not lead to long redirect chains, as these can lower SEO value and increase load times.

Additionally, perform regular audits and updates to review the necessity and functionality of existing redirects, to optimize site performance and crawling efficiency.

303 Status Code FAQs

What does the 303 Status Code mean?

The 303 status code tells the browser to “look elsewhere” after submitting data. It redirects the browser to a new URL to prevent resubmitting the same data if the original page reloads.

What is the difference between a 302 and 303 status code?

A 303 status code instructs the client to use a GET method to fetch the resource at a different URI, regardless of the original request method.

In contrast, a 302 status code, which also denotes redirection, does not explicitly specify that the GET method must be used, possibly leading to method retention from the original request (e.g., POST).

Is a 303 status code appropriate for all types of redirects?

No, the 303 status code is specifically recommended for situations where the server requires the client to separate resource retrieval from other types of interaction. For example, as in form submission. Use other status codes (like 302 or 301) for general redirection purposes.

Is HTTP 303 cached?

HTTP 303 responses are not cached by default. They are used to temporarily redirect users to another URL, especially after a POST request. However, a 303 response can be cached if the origin server specifies that in the headers.

What should I check if the 303 status code persists even after modifications?

Ensure that all caches (browser and server-side) are cleared since cached redirects can sometimes cause old behavior to persist. Also, double-check that no intermediary proxies or CDNs override your server’s configuration.