Brotli Compressor
Free online Brotli compressor. Compress files to .br with quality 0–11 or decompress .br back to the original. Runs entirely in your browser — no upload, no install.
What is Brotli?
Brotli is a lossless compression algorithm created by Google. It was designed for HTTP content encoding and ships in every major browser and web server, but it also works as a general-purpose file compressor — usually beating gzip by 15–20% on text at comparable speeds. Files use the .br extension.
Are my files uploaded to a server?
No. Compression and decompression run entirely inside your browser tab on a WebAssembly build of the official Brotli codec. Your files never leave your device, and the tool keeps working once the page has loaded even without a connection.
Which quality should I choose?
Quality 0–2 are extremely fast for quick transfers, 4–6 offer the best speed-to-ratio balance (5 is the default), and 9–11 squeeze out the last bytes at a much higher time cost — level 11 is the setting web servers use for static assets that are compressed once and served many times.
How large can my file be?
Files up to 512 MB are accepted. Processing happens in a background worker thread so the page never freezes, but the memory available to your browser is the practical ceiling for very large inputs.
Why does the decompressed file end with .out?
A .br stream stores only the compressed bytes and no original file name. The tool therefore names the restored file after the uploaded archive with a .out extension — just rename it back if you know what the original was called.
Can I open the resulting .br with other tools?
Yes. The output is a standard Brotli stream, identical to what the brotli command-line tool produces at the same quality. Use `brotli -d file.br` on Linux, macOS or Windows, or any HTTP client that understands Content-Encoding: br.
Is Brotli better than gzip?
On text such as HTML, CSS, JSON and fonts, Brotli typically produces files 15–20% smaller than gzip at similar decompression speed. Its built-in dictionary of common web strings gives it an extra edge on web content, which is why browsers prefer br over gzip when a server offers both.
Why did my file barely shrink or even grow?
Already-compressed data such as JPEG photos, videos or archives contains almost no redundancy, so Brotli has nothing to remove and the small format overhead can even enlarge the file slightly. The tool always shows exact before/after sizes so you can keep whichever file is smaller.
How to Use Brotli Compressor
Brotli Compressor creates and restores .br files entirely in your browser with the official Brotli codec compiled to WebAssembly — nothing is uploaded and everything stays on your device.
- Stay on the Compress tab to make .br files, or switch to the Decompress tab to restore them; the Quality slider appears only in compression mode.
- Drag one or more files onto the drop zone, or click it to browse — each file can be up to 512 MB, and any file can be removed from the list again.
- Set the Quality slider from 0 to 11: 0 is fastest, 11 compresses hardest, 5 is the balanced default — the same scale as the brotli command-line tool.
- Click Compress files or Decompress files to process every file in the list; the first run downloads and starts the WebAssembly engine, then the browser caches it for later.
- Each output row shows the original size, the result size and the ratio — download files one by one, or press Download all when there are several results.
A .br stream does not keep the original file name, so restored files are named .out — rename the extension back once you know the real type.
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