Zstandard (Zstd) Compression Tool

Compress or decompress text or a file using Zstandard (zstd) — Facebook/Meta's modern compression algorithm — right in your browser. Pick a compression level from 1 (fastest) to 22 (best ratio) and see the size, ratio and timing stats for the result.

How to use it

1. Choose Compress or Decompress.
2. Paste text into the input box, or upload a file (the file takes priority over the text box when both are present). For Decompress, paste Base64-encoded Zstd data if you're not uploading a .zst file.
3. For Compress, set the Compression level slider — low levels compress almost instantly, high levels squeeze out a smaller file at the cost of speed.
4. Press Compress or Decompress, then download the result or copy the Base64/decompressed text.

Zstd vs gzip vs Brotli

Zstandard was built at Facebook to beat gzip on both speed and ratio at the same time, rather than forcing a choice between them:

• Gzip (DEFLATE) is the oldest and most universally supported, but it's slower to reach a given ratio than either Zstd or Brotli, and its own levels top out earlier.
• Zstd typically compresses faster than gzip at an equivalent ratio, and its high levels (19-22) can match or beat gzip's best output while still decompressing extremely quickly — that fast decompression, independent of the compression level used, is Zstd's signature trait.
• Brotli usually edges out Zstd on final size for text/web content (it's what your browser negotiates for HTTP responses), but Zstd compresses faster at comparable settings, which is why it's the default choice for things like log pipelines, backups, and Linux kernel/package compression where compression speed matters as much as the ratio.

There's no universally "best" choice — pick gzip for maximum compatibility, Brotli when final size matters most and compression happens offline, and Zstd when you need a strong ratio without giving up speed.

Free in your browser, private by default

The in-browser tool compresses and decompresses locally via WebAssembly — your text or file is never uploaded.

Is there an API?

Yes. The same functionality is available as a paid developer API (POST /v1/tools/zstd-compression) for automating Zstd compression in a script or backend. The API costs one credit per call; the in-browser tool on this page stays free.

What if I need a different compression format?

For gzip, zlib, or raw deflate instead, use the Gzip/Zlib/Deflate Tester. To shrink an image rather than a text file or archive, use the Image Compressor.