Your files stay on your Mac.
Convertessa takes your existing .tar archive and wraps it with XZ compression, producing a .tar.xz file. XZ uses the LZMA2 algorithm to reduce archive size without altering the files inside. Everything runs locally — no file ever leaves your Mac.
Drag one or more .tar archives into Convertessa, or point it at a folder to process every archive inside.
Pick TAR + XZ from the output list. Convertessa will write each result as a .tar.xz file alongside the original.
Click Convert. Convertessa compresses each archive on-device and saves the .tar.xz output. The source .tar files are left untouched.
Images, audio, video, documents, archives and eBooks — all converted natively, right on your Mac.
Pick a format you have — see everything Convertessa can turn it into.
Convert hundreds of files at once with per-type group defaults and individual overrides.
First-class support for HEIC, AVIF and WebP — encode and decode, both ways. Read JPEG XL and a dozen more modern formats too.
Drop files anywhere on the window. Native, instant, and exactly what you’d expect on a Mac.
Dial in compression, resolution and bitrate. Keep originals pristine or shrink for sharing.
Never overwrite a file by accident. Convertessa appends safe suffixes automatically.
Every job is logged locally. Re-run a previous conversion or revisit recent outputs in a click.
Bundle your converted files straight into a single ZIP, TAR or 7z — packaged and ready to share the moment a job finishes.
Right-click any file in Finder and choose Convert. A Quick Action handles it on the spot — no need to open the app first.
Shrink Convertessa to a tidy mini window that tucks into a corner — just a drop zone and a format picker for quick, one-off conversions.
No cloud. No account. No upload. Every conversion happens entirely on-device, using the power already in your Mac. What you convert is nobody’s business but yours.
Script conversions, wire them into your build, or batch a folder from the terminal. The same engine, no GUI required.
Read the full CLI documentation →Shrink Convertessa down to a small, focused window — drop, convert, done, with your recent conversions one click away.
macOS 14+ · Apple Silicon & Intel
New formats, new features, and fixes — every release, on the record.
No. Convertessa applies XZ compression to the TAR container itself. The names, permissions, and contents of every file inside remain exactly as they were in the original .tar archive.
Yes. Drop a folder onto Convertessa or run convertessa /your/folder --to tar.xz in the terminal. Every .tar file found in that folder is converted in one pass.
Never. Convertessa converts entirely on-device. No data is uploaded to any server at any point in the process.