Your files stay on your Mac.
Apple CAF packages lossless audio in a container designed for macOS and iOS. Converting to FLAC rewraps that audio into a format that plays natively on Linux, Windows, Android, and virtually every open-source media player — without touching the samples. Both formats are lossless, so every bit of the original recording survives the conversion.
Drag one file or an entire folder onto Convertessa. All audio is processed locally — nothing is uploaded.
Select FLAC from the output format list. Convertessa locks in the lossless FLAC target and queues every file for conversion.
Click Convert. Convertessa writes FLAC files to your chosen destination folder, preserving the original filenames and directory structure.
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. Both Apple CAF and FLAC are lossless formats. Convertessa transcodes the raw PCM samples directly — dynamic range, frequency response, and bit depth are unchanged.
Yes. Drop a folder onto Convertessa or run convertessa ./folder/ --to flac in the terminal to batch-convert every CAF file inside. Subdirectory structure is preserved in the output.
Never. Convertessa runs entirely on your Mac — no internet connection is required and no audio data leaves your machine.