.. _arch_overview_compression_libraries: Compression Libraries ===================== Underlying implementation ------------------------- Currently Envoy uses `zlib `_ and `brotli `_ as compression libraries. .. note:: `zlib-ng `_ is a fork that hosts several 3rd-party contributions containing new optimizations. Those optimizations are considered useful for `improving compression performance `_. Envoy can be built to use `zlib-ng `_ instead of regular `zlib `_ by using ``--define zlib=ng`` Bazel option. The relevant build options used to build `zlib-ng `_ can be evaluated in :repo:`here `. Currently, this option is only available on Linux.