GZIP Decompressor

Read a server's rotated access or error log, such as access.log.2.gz, without logging in to the server; open a CSV or JSON data export delivered compressed; get the SQL from a database backup to inspect or import elsewhere; unpack a compressed feed from a supplier or marketplace; or check the content of any .gz file before using it. After unpacking, open the result with the right tool — the CSV Viewer for spreadsheets of data, the JSON Formatter for JSON, or any text editor for logs and SQL. Each file is checked to be real gzip data first, so a renamed file or an incomplete download produces a clear message rather than a broken result. Several files can be unpacked in one go, and each keeps its own name.

Gzip can store the original file name inside the .gz. When it does, that name is used — reduced to the plain file name, so no folders or paths from the file are trusted. Otherwise the name is the .gz name without its extension.

A tiny .gz file can be crafted to unpack to many gigabytes and freeze a computer. The decompressor counts the output as it unpacks and stops when it passes a safe limit — a thousand times the file's size, never more than 2 GB — with a clear message. Ordinary files, even large logs and dumps that compress very well, are well within the limit.

A .gz holds a single file. A .tar.gz or .tgz is a TAR archive — many files and folders bundled together — that was then gzipped. Unpacking it here gives you the .tar; the TAR Extractor opens .tar.gz files directly and lists all the files inside, which is usually what you want. ZIP files are a different format: use the ZIP Extractor for those.

Decompression uses the DecompressionStream feature built into modern browsers, so even large files unpack quickly and stay on your device. Server logs, customer exports and backups are never uploaded. To create .gz files, use the GZIP Compressor.