About Brotli Compress & Decompress Online
Brotli is Google's compression format that ships with every modern browser and powers the `Content-Encoding: br` responses behind a huge share of the web. At its highest quality it typically beats gzip on text — HTML, JSON, JavaScript, and CSS — by a meaningful margin. This free online Brotli tool compresses and decompresses `.br` data right in your browser.
Paste a payload to compress, choose a quality level from 0 to 11, and read off the exact byte savings and ratio. Need to inspect a captured `br` response or round-trip a Brotli blob? Switch to Decompress, paste its Base64, and get the original text back.
Everything runs locally with a WebAssembly build of Google’s reference Brotli, so compression matches the real thing — and nothing is uploaded. Your input never leaves the device, so it is safe for private payloads, API responses, and proprietary data.
Features
- Compress and decompress Brotli (.br) with quality levels 0–11
- Live original → compressed size and compression-ratio readout
- Base64 in/out so compressed bytes round-trip as copyable text
- Backed by Google’s reference Brotli compiled to WebAssembly — accurate and fast, fully offline
- Your data never leaves the browser
How to use
- Choose Compress, then paste the text you want to shrink.
- Pick a quality level from 0 to 11 (11 compresses hardest).
- Read the original → compressed size and ratio badge, then copy the Base64 output.
- To reverse it, switch to Decompress and paste the Base64 of the Brotli bytes.
Frequently asked questions
Is Brotli better than gzip?
For text content like HTML, CSS, JavaScript, and JSON, Brotli at high quality usually produces smaller output than gzip thanks to a built-in dictionary and a larger window. Gzip can be faster to compress, which is why both are still widely used; browsers accept either via the Accept-Encoding header.
What does the quality level do?
Quality (0–11) controls how hard the compressor works. Higher levels search more thoroughly and usually yield smaller output at the cost of speed; 11 is the maximum. The level does not affect correctness — any quality decompresses identically.
Why is the output shown as Base64?
Compressed Brotli data is raw bytes that are not printable text, so the tool encodes it as Base64 to display and copy it safely. When you decompress, paste that same Base64 back in and you get the original text out.
Is my data uploaded anywhere?
No. All compression and decompression runs locally in your browser using a WebAssembly Brotli engine and the built-in TextEncoder/TextDecoder APIs. Your input never leaves your device.
Why does compressing tiny input make it larger?
Brotli adds a small amount of framing and metadata. For very short or already-compressed input there is nothing to squeeze, so that fixed overhead can make the output bigger — the ratio badge turns amber to flag it.
Related tools
Everything runs locally in your browser — your input is never uploaded.