Tricks and tips for everyone


Why do some headers start with X?

Why do some headers start with X?

Any computer that handles a message is allowed to append its own headers. By convention, if a system wants to add its own custom header, it starts with X-. This is so they can be sure their custom headers don’t accidentally take the name of any defined header, current or future.

Should I prefix headers with X?

RFC6648 recommends that you assume that your custom header “might become standardized, public, commonly deployed, or usable across multiple implementations.” Therefore, it recommends not to prefix it with “X-” or similar constructs.

Can I set custom HTTP header?

Custom HTTP headers can be used to filter requests or specify a value for the Accept header. Some endpoints employ custom HTTP headers to filter data returned by a GET or POST request.

What is the max header size?

What is the maximum size of HTTP header values?

Web Server Size Limit
Apache 8K
Nginx 4K-8K
IIS 8K-16K
Tomcat 8K – 48K

What is Content-Type in HTTP header?

The Content-Type representation header is used to indicate the original media type of the resource (prior to any content encoding applied for sending). In responses, a Content-Type header provides the client with the actual content type of the returned content.

How do I find Max HTTP header size?

Change HTTP header size Next, open a terminal and navigate to the directory where code for our server is saved. In the terminal type node –max-http-header-size=1024 server. js . If you now open URL in browser, you should see updated value of HTTP headers size.

Why do some HTTP headers start with X-?

Initially, it was recommended to begin naming custom headers with X- so that users would be aware that these headers were custom and not standardized. However, according to RFC 6648, this recommendation has since been deprecated.

How do you format an HTTP header?

An HTTP header consists of its case-insensitive name followed by a colon ‘:’, then by its value (without line breaks). Leading white space before the value is ignored.

What are custom HTTP headers?

Custom HTTP headers are commonly meant to provide additional information that may be pertinent to a web developer, or for troubleshooting purposes. These headers often times begin with X-, however, we’ll discuss naming convention further on.

What is the X-prefix used for in headers?

Custom proprietary headers have historically been used with an X- prefix, but this convention was deprecated in June 2012 because of the inconveniences it caused when nonstandard fields became standard in RFC 6648; others are listed in an IANA registry, whose original content was defined in RFC 4229.

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