Enabling Brotli HTTP response compression in Kong Gateway

How can I enable Brotli compression for responses from Kong?

Kong Gateway supports Brotli compression, bundling the ngx_brotli module with Kong. This allows users to enable Brotli compression in a manner similar to gzip. Below are the steps and configurations needed to enable Brotli compression in Kong:

1. Verify ngx_brotli Module is Loaded:

First, ensure that the ngx_brotli module is included in your Kong version by running the following command in your Kong container (substitute your own image tag, e.g. 3.14.0.0):

docker run -it --rm --user root kong/kong-gateway:3.14.0.0 nginx -V

1. Enable Brotli Compression

To enable Brotli compression, you need to set the following environment variables in your Kong configuration;

KONG_NGINX_PROXY_BROTLI: "on"
KONG_NGINX_PROXY_BROTLI_COMP_LEVEL: 4
KONG_NGINX_PROXY_BROTLI_TYPES: "*"

These settings activate Brotli compression, set the compression level to 4, and enable compression for all MIME types.

1. Testing Brotli Compression

After enabling Brotli compression, you can test it by making an API call with the Accept-Encoding: br header. To view the uncompressed output, pipe the response through a Brotli decompressor:

curl -v -H "Accept-Encoding: br" http://proxy.kong.lan:8000/httpbin/anything | brotli -d

In the response you will see the Content-Encoding: br header indicating that the response was compressed using Brotli compression.

Without piping the output to the decompressor, the response will be in binary format, indicating the compressed data.

In summary, enabling Brotli compression in Kong is straightforward thanks to the bundled ngx_brotli module. By setting the appropriate environment variables, users can optimize their API traffic using this efficient compression method. For gzip and potentially other compression methods, users should consult Kong’s documentation for guidance and support.