IIS Brotli

Google Brotli compression module for Microsoft IIS

Brotli is an open source data compression library from Google, it improves on gzip's compression ratio by roughly 17-25%.

We-Amp B.V. has made Brotli available for Microsoft IIS. You can either install it in IIS as compression scheme or native http module.


  • Brotli compression improves on the built-in IIS gzip compression ratio by roughly 17-25%.
  • Brotli -11 density compared to gzip -9:
    HTML (multi-language corpus): 25 % savings
    Javascript (Alexa top 10k): 17 % savings
    Minified js (Alexa top 10k): 17 % savings
    CSS (Alexa top 10k): 20 % savings

Brotli browser support

Brotli encoding is currently only requested by browsers for https requests, to avoid trouble with bad intermediaries (proxies).
- Firefox: 44+
- Chrome: 49+ (not by default, but can be enabled)