What Is HTTP 411 Status Code (Length Required Error)?

Reliqus Marketing

08 April 2024

HTTP Status Codes
By Ankit Bhatia
Founder & CEO

You may have encountered various error codes when browsing the internet, including the 411 Status Code or “Length Required” error. This error can be frustrating as it can prevent you from accessing a website or completing a transaction. 

But what does this error mean? 

The 411 status code is an HTTP response that indicates that the server cannot handle the request because the content length is not specified. This response status code is part of the HTTP/1.1 standard and serves as a communication issue identifier between the client and the server. Specifically, it centers around the Content-Length header in the HTTP request.

When a request is sent to a server, it is generally expected to include a Content-Length header, which informs the server of the size of the data being sent in the request body. The requirement for this header is to ensure that the server can properly process and understand the request.

If a request is made without specifying the Content-Length, or if the information provided is deemed insufficient by the server, the server may respond with a Status Code 411

HTTP 411 Status Code References

Implementing and responding to the 411 Length Required HTTP status code varies across different programming languages and frameworks. Each has its way of representing and handling HTTP status codes, including 411.

Below is a concise guide on how the status code 411 is referenced across various platforms and technologies, providing a useful snippet for developers working in these environments:

– Rails HTTP Status Symbol :length_required 

– Go HTTP Status Constant http.StatusLengthRequired 

– Symfony HTTP Status Constant Response::HTTP_LENGTH_REQUIRED 

– Python2 HTTP Status Constant httplib.LENGTH_REQUIRED 

– Python3+ HTTP Status Constant http.client.LENGTH_REQUIRED 

– Python3.5+ HTTP Status Constant http.HTTPStatus.LENGTH_REQUIRED 

– .NET HttpStatusCode.LengthRequired 

– Rust http::StatusCode::LENGTH_REQUIRED 

– Java java.net.HttpURLConnection.HTTP_LENGTH_REQUIRED 

– Apache HttpComponents Core org.apache.hc.core5.http.HttpStatus.SC_LENGTH_REQUIRED 

– Angular @angular/common/http/HttpStatusCode.LengthRequired

What are the Related HTTP Response Headers for a 411 Status Code?

In the context of a 411 Length Required status code, it’s essential to be aware of related HTTP response headers. These headers can offer additional details regarding the request and its status, which is crucial in diagnosing issues and providing context about the encountered error.

When dealing with a status code 411, the following HTTP response headers are particularly noteworthy:

  • Content-Type: This specifies the media type of the resource or data involved in the request or response. Understanding the content type can help determine whether the content length should be expected.
  • Content-Length: This header is directly related to the 411 error, as it indicates the body size in bytes. The absence or misconfiguration of this header is often the root cause of a 411 Length Required status code.
  • Transfer-Encoding: This header specifies the form of encoding used to safely transfer the payload body to the user. A misunderstanding or misapplication of this header can lead to issues with content length requirements.
  • Server: Provides information about the software being used by the origin server. While not directly related to the 411 error, understanding the server context can help diagnose and fix issues that may contribute to this status code.

Understanding and correctly implementing these headers is a delicate balance, one that requires not just technical knowledge but also practical experience. This is where Reliqus Consulting steps in. 

Our expertise in web development ensures that your website adheres to the correct protocols, preventing errors such as the 411 Length Required. By ensuring your site’s communication with clients is clear and compliant with HTTP standards, we help maintain its accessibility and performance at the highest levels. 

Trust us to safeguard your online presence against common pitfalls, making your web infrastructure robust and reliable.

The Common Causes Of The 411 Length Required Error

Several common causes of the 411 Length Required status code can stem from client or server issues. Understanding these causes can help identify and fix the issue more efficiently. 

Below are some of the primary reasons why a 411 error might occur:

  • Missing or Incorrect Content-Length Header: The most straightforward cause is simply that the HTTP request does not include a `Content-Length` header when attempting to submit data via methods such as POST or PUT, which inherently require the content size of the request body to be specified.
  • Incorrect Configuration: Sometimes, the server or web application settings are configured to require a Content-Length header for all requests, including those that do not typically require it. This misconfiguration can lead to unnecessary 411 errors even when the client’s request should be valid.
  • Network Issues: Though less common, network issues can lead to incomplete requests or the stripping of headers. This will likely be a broader issue affecting multiple requests and responses, not just those related to the 411 status code.
  • Intermediate proxy or firewall interference: Sometimes, the request initially leaves the client with the correct headers, but an intermediate proxy or a firewall modifies the request or strips out headers, including the `Content-Length`. This can happen in corporate networks, with certain security appliances, or even with some internet service providers.

Identifying the cause is the first step toward resolving the 411 Length Required error, enabling smoother web browsing experiences. 

Similarly, request size or format issues not only lead to 411 errors but can also trigger a 414 URI Too Long status code when the request’s URI exceeds the server’s interpretative capacity.”

4 Methods To Prevent The 411 Length Required Error

Preventing the 411 Length Required error involves ensuring that HTTP requests are correctly formed, mainly when they include a body of data. 

Here are four practical methods to help avoid encountering this error:

1. Check The Request Headers

Before sending a request, especially with methods like POST or PUT, verify that the `Content-Length` header is correctly included and accurately reflects the size of the body content in bytes. 

This is crucial for informing the server of the size of the request body.

2. Verify Intermediate Proxy or Firewall Settings

If your requests are routed through intermediate proxies or firewalls, ensure that these devices are configured not to strip or alter essential headers like `Content-Length`. 

Misconfigured proxies or firewalls can inadvertently remove these headers, leading to 411 Status Code errors.

3. Utilize Appropriate HTTP Methods

Be mindful of the HTTP method used for each request. GET requests, for example, should not have a body, and thus, sending a `Content-Length` header with a GET request might be inappropriate. 

Conversely, ensure the body and the’ Content-Length’ header are correctly included for methods expected to carry a payload (like POST or PUT).

4. Update To The Latest Versions Of Software Or Libraries

Using outdated software or libraries can lead to many issues, including improperly formed HTTP requests. Updates often include patches for bugs that could be causing incorrect handling or omission of headers like `Content-Length`.

While these strategies can significantly reduce the likelihood of encountering a 411 Length Required error, staying informed about evolving HTTP standards and practices is also essential. Continuous learning and adaptation to new technologies and methodologies will enhance your ability to efficiently and effectively manage HTTP communications.

Related HTTP Response Headers

Understanding the 411 Length Required error also involves familiarizing yourself with related HTTP response headers. These headers play a significant role in the communication between clients and servers, especially concerning content negotiation and transfer. 

Here are four crucial HTTP response headers related to the status code 411:

1. Content-Type:

The `Content-Type` header is used in HTTP responses to indicate the media type of the associated resource

When dealing with a request that leads to a 411 error, ensuring that the `Content-Type` header accurately reflects the type of data being communicated is essential.

2. Content-Length:

The `Content-Length` header is crucial in both HTTP requests and responses. It specifies the exact byte length of the HTTP body. A 411 Length Required error explicitly concerns this header’s absence in a request. 

However, ensuring it’s accurately set in responses is also vital for clients to correctly process received data.

3. Transfer-Encoding:

The `Transfer-Encoding` header specifies the encoding used to safely transfer the payload body to the user. A common value for this header is `chunked,` which allows the data to be sent in chunks. 

This header is particularly relevant when the size of the response body is not known in advance, making it impossible to use the `Content-Length` header.

4. Server:

The `Server` header contains information about the software used by the origin server to handle the request

While not directly related to handling content length or type, it can provide additional context in troubleshooting scenarios, especially when determining compatibility or specific server behaviours.

411 Status Code and SEO

When considering the 411 Length Required status code from an SEO perspective, it’s essential to understand its implications and how it can indirectly affect your website’s search engine ranking and user experience.

Just like the nuanced impacts of the 410 Gone status code, the 411 error serves as a reminder of the delicate balance between server-client communication and the broader implications for site visibility and user engagement.

Impact on Crawlers

Search engine crawlers, like Googlebot, aim to index content efficiently. Encountering a 411 error can hinder this process, preventing crawlers from accessing and indexing content correctly.

If a crawler frequently runs into 411 Status Code errors on your site, it may reduce the crawl rate or even omit affected pages from the index, negatively impacting your site’s visibility.

User Experience

Although a direct relationship between HTTP status codes and SEO rankings is complex and not explicitly defined by search engines, user experience (UX) plays a crucial role in SEO

Pages that return a 411 error contribute to a poor user experience, potentially increasing bounce rates and reducing the time spent on the site. Search engines consider these user interaction signals when determining rankings.

Best Practices for Mitigation

  1. Monitor and Audit: Regularly use tools to crawl your site like search engines do. Identifying and fixing status code 411 errors promptly can prevent negative SEO impacts.
  2. Correct Configuration: Ensure your server and website code correctly handle HTTP headers, especially for POST and PUT requests, to avoid unnecessary 411 errors.
  3. Redirects: In cases where a 411 status code error might occur due to legacy issues or specific configurations, consider implementing server-side redirects to more appropriate URLs or error-handling mechanisms that offer a better user experience.
  4. Communicate with Users: If a 411 error is unavoidable in certain situations, provide clear, user-friendly error messages and options for users to continue navigating your site. This can help mitigate negative UX impacts.
  5. Technical SEO Audit: Include HTTP status codes in regular SEO audits. Tools that simulate how search engines crawl your site can help identify not just 411 errors but a range of issues that could impact SEO.


In wrapping up our exploration of the 411 Length Required status code, it’s clear that understanding and managing HTTP status codes is more than a technical necessity; it’s a fundamental aspect of maintaining a healthy, user-friendly, and search-engine-optimized website. 

While the 411 status code is specific and perhaps less frequently encountered than other HTTP errors, it underscores the importance of precise communication between clients and servers.

For website owners, developers, and SEO specialists alike, the journey doesn’t stop with resolving one error or implementing a single best practice. It’s an ongoing adaptation, learning, and optimization process that ensures the web remains an open, accessible, and valuable resource for all.

Frequently Asked Questions (FAQ)

Navigating through the complexities of HTTP status codes can sometimes leave us with more questions than answers. To help clear up any confusion, here are some of the most frequently asked questions about the 411 status code, providing you with quick, straightforward insights and solutions.

What is the 411 Length Required Status Code?

It’s an HTTP response status code indicating that the server refuses to accept the request because the “Content-Length” header is missing.

How do we Resolve the 411 Length Required?

Ensure that HTTP requests include a valid Content-Length header that accurately reflects the size of the request body.

How do you Calculate Content-Length?

The content length is calculated as the number of octets (8-bit bytes) in the body of the request or response. Tools and programming languages typically offer functions to calculate this automatically.

What is the Browser’s Compatibility with the 411 HTTP Status Code?

All modern web browsers, including Chrome, Edge, Firefox, Internet Explorer, Opera, Safari, and Webview Android, correctly handle the 411 HTTP status code, as it’s part of the HTTP/1.1 standard supported universally.

Ankit Bhatia

Founder & CEO at Reliqus

With 12+ years of experience building a web presence for 300+ businesses, Ankit understands how businesses can use technology to increase revenue.

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