HTTP headers | ContentEncoding (original) (raw)

HTTP headers | Content-Encoding

Last Updated : 12 Jul, 2025

The HTTP headers Content-encoding is used to compress the media type. It informers the server which encoding the user will supported. It sends the information to the Accept-encoding. The server selects any one of the proposals, uses it and informs the client of its choice with the Content-Encoding response header.Syntax:

Content-Encoding: gzip | compress | deflate | br| identity

Note: Multiple algorithms can also be applied.Directives:

• gzip: It uses Lempel-Ziv coding (LZ77), with a 32-bit CRC format. It is the original format of UNIX gzip program.
• compress: It uses Lempel-Ziv-Welch (LZW) algorithm. Due to patent issue, many modern browsers don't support this type of content-encoding.
• deflate: This format uses zlib structure with deflate compression algorithm.
• br: It is a compression format using the Brotli algorithm.
• identity: It is used to indicate that there is no compression.

You can check how good your Accept-Encoding and Content-Encoding is working on this site. Example:

• Single Compression:
  Content-Encoding: gzip
  Content-Encoding: compress
• Multiple Compression:
  Content-Encoding: gzip, compress

To check the Content-Encoding in action go to Inspect Element -> Network check the request header for Content-Encoding like below, Content-Encoding is highlighted you can see. Supported Browsers: The browsers compatible with HTTP headers Content-Encoding are listed below:

• Google Chrome
• Internet Explorer
• Firefox
• Safari
• Opera