Brotli is an open source data compression library from Google, it improves on gzip's compression ratio by roughly 17-25%.
Like gzip, brotli is based on the deflate algorithm, which is a combination of LZ77 and Huffman coding. It was first released for WOFF2 compression of web fonts. Since September 2015 Brotli is suitable for HTTP compression, so it can be used to compress webserver responses sent to a browser.
Brotli is no less than "a whole new data format" that is able to pack significantly more data while also decompressing it at a competitive speed. It uses a pre-defined 120 kilobyte dictionary, this contains over 13000 common words, phrases and other substrings derived from a large corpus of text and HTML documents.
Brotli browser support
- Firefox: 44+ (on by default)
- Chrome: 49+ (not by default, but can be enabled)
- Edge: 15+ (on by default)
Like zopfli, another compression algorithm from Google, Brotli is named after a Swiss bakery product, brötli.