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Compress and decompress Zstandard online

Create .zst files or decompress a supported Zstandard frame with local WebAssembly processing.

On-device processing

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Drop your files right here

or choose one from your device

64.0 MiB total · No upload required

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Format

Zstandard: up to 64 MiB to compress, 128 MiB expanded. Single frames only; no external dictionaries. Use Create archive to bundle several files.

Ready when you are.

Free, without file credits

Files processed locally

ZIP, 7z, RAR & Zstandard

Privacy, compatibility & limits

File contents and passwords are processed in a dedicated worker in your browser. They are not uploaded, logged, or saved by this app. Downloads remain available until you change the operation or close the page. Your browser manages downloaded files. The web server may log ordinary page requests; no analytics, ads, or AI scripts are enabled in this version.

Input limit: 128 MiB total and 500 files. ZIP extraction is limited to 500 entries and 256 MiB of expanded data. Operations stop after two minutes, or when you cancel. 7z and Zstandard creation have a 64 MiB input limit. Zstandard extraction is limited to 128 MiB with single frames and no external dictionaries. Very large archives, nested extraction, and split archives are outside this version’s scope. RAR is extraction-only. Modern browser support is required.

Password protection uses AES-256 via zip.js for ZIP and 7-Zip WebAssembly for 7z. ZIP filenames and file sizes are visible; 7z can encrypt its file listing too. Password-protected ZIP compatibility varies by archive app; there is no password recovery. An external security review is still needed before making stronger security assurances.

All file tools

How to compress and decompress Zstandard online

Choose one file and keep Zstandard selected.
Choose Compress to .zst, or Decompress .zst for an existing compressed file.
Process the file and save the result.

Before you start

File processing happens on your device. File contents and passwords are not uploaded to FileLance. Your original files stay unchanged; save the results before leaving the page. Large files can use significant browser memory, especially on phones.

Does Zstandard bundle several files?

This tool compresses one file at a time. Use ZIP or 7z to bundle several files. Decompressing a .tar.zst produces a tar file; this tool does not unpack the tar archive.

Which Zstandard files are supported?

This version accepts single frames without external dictionaries. Concatenated frames and skippable frames are unsupported.

What are the size limits?

Compression input is capped at 64 MiB. Decompression input is capped at 128 MiB, and both the declared window and expanded output must fit within 128 MiB.

Free browser file tools

Choose a task for the right tool, instructions, and format limits.

Extract RAR files onlineOpen RAR and RAR5 archives in your browser, select the files you need, and save them without uploading your archive.Open 7z files onlineExtract files from a 7z archive locally, including password-protected archives when you know the password.Unzip files onlineBrowse a ZIP archive and extract selected files on your device. No account or file upload required.Create a ZIP file onlineCombine multiple files into a ZIP archive in your browser. Choose a compression level and download one bundle.Create a 7z archive onlineBundle files into a 7z archive using LZMA2 compression through WebAssembly on your device.Compress and decompress Zstandard onlineCreate .zst files or decompress a supported Zstandard frame with local WebAssembly processing.Compress and decompress gzip onlineCompress one file to .gz or restore a gzip-compressed file in your browser without sending its contents to a server.Password-protect a ZIP fileCreate an AES-256 encrypted ZIP from your files, with encryption performed locally in your browser.