Simple wrapper on top of express.static, that allows serving pre-gzipped files as well as other types of compressions.
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Provides a small layer on top of serve-static, which allows to serve pre-gzipped files. Supports brotli and any other compressions as well.


For the express-static-gzip middleware to work properly you need to first ensure that you have all files gzipped (or compressed with your desired algorithm), which you want to serve as a compressed version to the browser. Simplest use case is to either have a folder with only .gz files, or you have a folder with the .gz files next to the original files. Some goes for other compressions.


    $ npm install express-static-gzip


In case you just want to serve gzipped files only, this simple example would do:

var express = require("express");
var expressStaticGzip = require("express-static-gzip");
var app = express();

app.use("/", expressStaticGzip("/my/rootFolder/"));

While gzip compression is always enabled you now have the choice to add other types of compressions using the options object. Currently brotli can be enabled using the options.enableBrotli flag. All other compressions need to be added by passing an array to options.customCompressions. The options object is also passed to the express.static middleware, in case you want to configure this one as well.

The following example will show howto add brotli and deflate(with file extension .zz) to the middleware (it will still support gzip):

var express = require("express");
var expressStaticGzip = require("express-static-gzip");
var app = express();

app.use("/", expressStaticGzip("/my/rootFolder/", {
    enableBrotli: true,
    customCompressions: [{
        encodingName: "deflate",
        fileExtension: "zz"

Compressions are selected in the following order if a file is requested from the middleware:

  • any custom compression in the order they are provided to options.customCompressions
  • brotli (if enabled via options.enableBrotli)
  • gzip
  • plain file (in case no compression exists or none is matching the browsers accepted encodings header)

When the middleware is created it will check the given root folder and all subfolders for files matching the registered compression. Adding files later to the folder will not be recognized by the middleware.

Behavior warning

In default mode a request for "/" or "<somepath>/" will now serve index.html as compressed version. This could lead to complications if you are serving a REST API from the same path, when the express-server-static is registered before your API.

One solution would be to register express-server-static last. Otherweise you can set options.indexFromEmptyFile to false:

app.use("/", expressStaticGzip("/my/rootFolder/", { indexFromEmptyFile: false }));


In case you have the following basic file structure

  • rootFolder
    • index.html
    • index.html.gz
    • test.html.gz
    • main.js

and you use set the enableBrotli flag to true, express-static-gzip will answer GET requests like this:

GET / >>> /my/rootFolder/

GET /index.html >>> /my/rootFolder/

GET /test.html >>> /my/rootFolder/test.html.gz

GET /main.js >>> /my/rootFolder/main.js