Compress or decompress Zstandard (.zst) files up to 2 GiB in your browser, with a level from -7 to 4.
Runs in your browser — your input is processed on this device and never uploaded.
Pasted text up to 100 MiB, read as UTF-8, or a file up to 2 GiB.
Results appear here.
Zstandard is a compression format from Facebook, published in 2016. Files usually end in .zst. It compresses quickly and decompresses even faster, which is why it shows up in Linux packages, databases and backups.
This tool compresses bytes into a Zstandard frame, or decompresses a Zstandard frame back to the original bytes.
The zstd command goes up to level 19, or 22 with --ultra. This page runs a pure Rust codec inside your browser and offers levels -7 to 4. Frames it writes stay at an 8 MiB window. It will still open a frame that asks for up to 128 MiB.
Speed is the reason most people pick Zstandard. In our tests on a desktop computer, 100 MiB of text compressed at level 3 in under a second, to about 28 MiB.
Gzip (.gz) is older and opens almost everywhere. Brotli (.br) is common for web content. LZ4 (.lz4) is faster still, with larger files. Each of those has its own tool on this site. XZ (.xz) usually makes smaller files but takes much longer, and this page does not open it.
The zstd command on your computer does the same job for files larger than 2 GiB, and it can use the higher levels, long-distance matching and dictionaries.
Yann Collet created Zstandard. He also wrote LZ4. The format is RFC 8878, which replaced RFC 8478.
Some programs compress with a shared dictionary file that both sides must have. A frame made that way is rejected here, because this page has no way to load the dictionary.
A frame can carry a checksum of the original bytes, which catches a damaged or truncated download. It does not tell you who made the file, and it is not a signature.
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