What this does
Compresses text or files with Brotli (RFC 7932) and decompresses Brotli data, in your browser. Output is shown as Base64 or hex and can be downloaded as a .br file. The same tool also handles gzip, zlib and raw deflate through the format menu.
About Brotli
Brotli was designed for the web. It ships with a built-in dictionary of common HTML, CSS, JavaScript and English words, so it typically beats gzip by 15-25% on text assets and is served as Content-Encoding: br by most CDNs. Quality runs from 0 (fastest) to 11 (smallest, slowest); 4-6 is a common dynamic-content setting and 11 is typical for static files compressed once at build time. This tool defaults to 5 so large inputs stay quick.
Decompressing and safety
Paste Base64 or hex, or open a file. Brotli has no magic number, so choose Brotli explicitly or use automatic detection, which tries raw deflate first and then Brotli. Corrupt or truncated streams produce an error. Decompression stops at 64 MiB of output as protection against decompression bombs.
How it is loaded
Brotli runs as a WebAssembly module of about 1 MB (roughly 500 KB compressed). It is loaded on demand inside a background worker the first time you use Brotli, so pages that do not use it never download it. If your network blocks it, you will see an error rather than a silent failure.
Privacy
Everything is computed locally and nothing is uploaded.