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pixz (parallel indexed xz) file format

.tpxz  ·  archive+compression  ·  introduced 2010 by Jonathan Nieder

What is a pixz (parallel indexed xz) file?

pixz is a parallel XZ compressor optimized for tar archives. It compresses each block in parallel and writes an index that maps file paths to byte offsets, enabling random-access extraction of individual files from a multi-gigabyte tarball without scanning the whole thing.

Most readers reach this page after double-clicking a .tpxz file and finding their operating system unsure what to do with it. The good news: pixz (parallel indexed xz) is a well-understood format with mature tooling on every major platform. It is supported in one click by mainstream archivers on Windows, macOS, and Linux.

How to extract a pixz (parallel indexed xz) file

Opening a .tpxz file is straightforward on every modern operating system. The exact steps depend on which platform you are on:

On Windows

  1. Locate the .tpxz file in File Explorer.
  2. Right-click the file. If you have 7-Zip installed, choose 7-Zip → Extract Here. On Windows 11 the built-in extractor handles ZIP, 7z, RAR and several other formats directly through Extract All…
  3. If prompted, pick a destination folder and click Extract.
  4. The extracted files appear in a folder next to the original archive.

On macOS

  1. Find the .tpxz file in Finder.
  2. Install The Unarchiver from the Mac App Store, or Keka for both creating and extracting.
  3. Right-click the file → Open With → The Unarchiver (or just double-click after Unarchiver is set as the default).
  4. The extracted folder appears next to the archive.

On Linux

  1. Use your file manager: right-click the archive → Extract Here (file-roller on GNOME, Ark on KDE).
  2. On the command line, run one of: 
    7z x archive.tpxz    # works for almost any format
  3. The files appear in the current directory.

How to create a pixz (parallel indexed xz) file

To pack files into a .tpxz archive, you typically need an archiver that supports writing this format. Not every tool can create every format — for example, only WinRAR can create real RAR files. The sidebar lists the software known to read and write pixz (parallel indexed xz).

On the command line, the canonical create command is:

# Use 7-Zip, PeaZip, or the format's reference tool to create .tpxz files.

If you regularly create archives at scale, a dedicated archive automation suite can wrap this command in scheduled jobs, integrity checks, and offsite replication.

Strengths

  • Parallel compression and decompression
  • Indexed random access

Weaknesses and limitations

  • Only useful for tar.xz workloads
  • Less common than xz

Typical use cases

  • Compressing huge tarballs where you need random extract

Technical details

pixz (parallel indexed xz) uses the TAR + parallel XZ + index algorithm and is identified on disk by the magic byte sequence FD 37 7A 58 5A 00. The standard MIME type is application/x-xz. The format is an open specification and is free for any use.

Frequently asked questions

Is pixz (parallel indexed xz) safe to open?

Archive files are containers — they are only as safe as what they contain. A .tpxz from a trusted source is fine; one received from a stranger can hold malicious executables, scripts, or files engineered to exploit bugs in your archiver. Always keep your archiver updated, and never run unknown executables that come out of an archive. A safe workflow is to extract into a sandbox and scan the contents before opening anything.

What is the maximum file size?

Modern implementations support archives in the multi-terabyte range. The practical limit is your filesystem (FAT32 caps at 4 GB; ext4, NTFS, APFS, and exFAT all comfortably handle multi-TB files).

Can I password-protect a pixz (parallel indexed xz)?

Some archivers can wrap pixz (parallel indexed xz) files in an encrypted container, but the format itself does not always include built-in encryption. Check your archiver's documentation.

How does pixz (parallel indexed xz) compare to other formats?

See our format comparison pages such as ZIP vs 7z, ZIP vs RAR, and tar.gz vs tar.xz for side-by-side feature tables.

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