HTTP 499 Status Code: What It Means and How to Fix It

HTTP 499 status code is a stand-out case among the HTTP error codes. Officially logged as “499 Client Closed Request” and used by the NGINX server, this status code indicates that the client request was closed before the server could send a response.

A handful of potential causes can lead to the HTTP 499 Status Code. If you continue to receive it, there are a few things you should check and fixes that can help solve the underlying issue.

What Is HTTP Status Code 499

HTTP status code 499 indicates that the client has closed the connection while the server was still processing the request. Typically, this HTTP status is considered a client-side error, signaling that the request termination occurred on the client side.

HTTP 499 error code is not a standard HTTP error code. The standard HTTP specifications are primarily defined by the Internet Engineering Task Force and are used universally.

On the other hand, the HTTP status code 499 is defined by and for NGINX, a high-performance web server that also functions as a reverse proxy.

Companies use NGINX to make websites faster and more reliable when handling multiple requests. Since HTTP status 499 indicates the client disconnected early, this error code is not visible on the client side but appears in NGINX logs to indicate the premature termination of the HTTP request.

When and Why Does a 499 Error Occur

A few common scenarios why you may be seeing this error code in your log files include:

• User actions: the user could have just closed the browser, hit the back button, or navigated away.
• Interrupted session: for example, the user may have been logged out mid-request.
• Client-side timeout: the server may have exceeded the app or API’s HTTP request limit, causing the connection to drop.
• Limits set by automated scripts: a client-side timeout may also indicate that an automated program on the user’s side is making the request and then canceling it before a response is received.
• Network instability: a poor and unstable network connectivity can lead to a lost connection, logging an HTTP 499 error.
• Slow server: if the server is too slow to respond, this may lead to a spike in dropped requests, logged as 499 errors.

Some of these causes for the HTTP 499 status are simply regular web traffic, while the latter should be fixed as soon as possible.

How to Fix and Prevent HTTP 499 Errors

There are several steps you can take to reduce the likelihood of HTTP 499 status code errors. If you are already seeing such an error or a spike in them, you can also try a few fixes.

Check Server Logs

To troubleshoot the HTTP 499 error, first check the server logs if you have access. Server log entries that coincide with the time when the HTTP 499 status code was returned may provide clues into the cause of the issue.

Upgrade Your Server or Proxy Performance

Slow server or proxy response times may lead clients to abort requests. In this case, 499 errors indicate a serious issue for websites. You can upgrade your servers, change your hosting service or proxy provider, or utilize a load-balancing service to distribute traffic across multiple servers.

Review Timeout Configurations

Since server or client-side timeouts are among the leading causes of 499 status errors, you can reduce them by increasing your timeout value. Check your timeout configurations and, if practicable, adjust them to allow for a longer wait before dropping the HTTP request.

Check the Network Connection

HTTP 499 status code also has fixes on the client side. Check the network connection to make sure it’s stable. You can also try accessing the webpage with another device.

Clear the Browser Cache

A cached resource can cause the 499 error. Clear the browser cache and cookies, and try accessing the webpage again. You may also try disabling browser extensions and plugins.

What’s the Difference Between 499 and Other Status Codes

Status codes starting with 4, like 499, indicate a client-side error. As mentioned, however, status code 499 is not a typical HTTP error code and has different origins than the most common 4xx codes.

For example, one of the most common status codes, 403 Forbidden , indicates that the server understands the request but refuses it because the client lacks the necessary permissions. Meanwhile, code 415 indicates that the request was dropped due to a missing or incorrect header.

In both cases, the server denies the request, recognizing a client-side error. In case of status 499, it is the client that drops the request.

HTTP status code 444 No Response , while also a non-standard NGINX-specific status code, means the exact opposite of code 499. In case of status code 444, NGINX (not the client) drops the request but returns no response.

The 499 error may also be confused with some standard HTTP proxy error codes , especially 504 Gateway Timeout, which happens when the proxy or gateway times out.

A timeout might cause both errors, but in the case of the 504 error, it is always on the gateway side. Similarly, 505 code indicates that the client and server cannot agree on the HTTP protocol to use, so the connection is dropped.

Should You Be Concerned About Status Code 499?

An occasional status 499 error is nothing to worry about. Clients will sometimes drop requests; that is just part of browsing. What you should pay attention to is sudden spikes in 499 errors. They may signal a bigger issue that needs to be solved.

Additionally, if 499 errors are quite frequent, you may also want to check your server configurations or otherwise investigate for a root cause. You may be losing traffic due to some issues that could be fixed once you identify them.

Summing Up

The HTTP 499 status code signals that the client has dropped the request, but the underlying issue may in fact be with the server or the proxy. If the error code persists, you can detect and fix the cause using one of the aforementioned methods.