Your files stay on your Mac.
Convertessa takes your MP3 files and outputs them as MKA Matroska audio containers. Set the quality level to control how the audio is encoded. Every file stays on your Mac — no upload, no cloud processing, no internet required.
Drag one MP3 or an entire folder onto Convertessa. Batch mode queues every file at once.
Choose Matroska from the output list, then set the quality level if needed.
Click Convert. Convertessa processes each file locally and saves the MKA files beside the originals.
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.
Higher quality values produce larger files with better audio fidelity; lower values reduce file size. You can adjust the quality setting before running a batch so every output file meets your target.
Yes. Drop a folder onto Convertessa or run convertessa ./folder --to mka from the command line to convert every MP3 in the directory in one pass.
Yes. Convertessa runs entirely offline — no file is ever uploaded to a server or cloud service. Conversion happens locally on your Mac.