Jetty Logo
Version: 9.4.31.v20200723
Contact the core Jetty developers at

private support for your internal/customer projects ... custom extensions and distributions ... versioned snapshots for indefinite support ... scalability guidance for your apps and Ajax/Comet projects ... development services for sponsored feature development

Gzip Handler

Gzip Rules
Gzip Configuration



The Jetty GzipHandler is a compression handler that you can apply to any dynamic resource (servlet). It fixes many of the bugs in commonly available compression filters: it works with asynchronous servlets; it handles all ways to set content length. It has been tested with Jetty continuations and suspending requests. Some user-agents might be excluded from compression to avoid common browser bugs (yes, this means IE!).

The GzipHandler can be added to the entire server by enabling the gzip.mod module. It may also be added to individual contexts in a context xml file.


Jetty 9 only compresses using GZip. Using deflate HTTP compression is not supported and will not function.

Gzip Rules

GzipHandler will gzip the content of a response if:

  • It is mapped to a matching path
  • The request method is configured to support gzip
  • The request is not from an excluded User-Agent
  • accept-encoding header is set to gzip
  • The response status code is >=200 and <300
  • The content length is unknown or more than the minGzipSize initParameter or the minGzipSize is 0(default)
  • The content-type does not match an excluded mime-type
  • No content-encoding is specified by the resource

Compressing the content can greatly improve the network bandwidth usage, but at the cost of memory and CPU cycles. The DefaultServlet is capable of serving pre-compressed static content, which saves memory and CPU.

The GzipHandler installs an output interceptor which passes through to the DefaultServlet. If the content served by DefaultServlet is already compressed, the GzipHandler does nothing; if it is not compressed, the content is compressed on-the-fly.


Automatic precompression by the DefaultServlet can be configured. Read more about the DefaultServlet here.

Gzip Configuration

Content will only be compressed if content length is either unknown or greater than minGzipSize.
checkGzExists (Deprecated)
False by default. If set to true, the handler will check for pre-compressed content.
List of HTTP methods to compress. If not set, only GET requests are compressed.
List of MIME types to compress.
List of MIME types not to compress.
A list of regex patterns for User-Agent names from which requests should not be compressed.
List of paths to exclude from compression. Performs a String.startsWith(String) comparison to check if the path matches. If it does match then there is no compression. To match subpaths use excludePathPatterns instead.
List of paths to consider for compression.
List of paths to definitely consider for compression.

See an error or something missing? Contribute to this documentation at Github!(Generated: 2020-07-23)