Your files stay on your Mac.
EPUB is the open ebook standard; Kindle devices and apps read MOBI. Convertessa rewrites the container, chapter structure, and embedded assets so the result opens natively on any Kindle or the Kindle app. Every step runs on your Mac—no file ever leaves your machine.
Drag one EPUB or an entire folder of EPUBs onto Convertessa. The app reads each source file and queues every book for conversion.
Pick Kindle MOBI from the output list. Optionally set quality for embedded images—handy when your EPUBs contain illustrations, comics, or photo-heavy layouts.
Click Convert. Convertessa processes every queued file locally and saves the MOBI files alongside the originals. No server, no waiting for an upload.
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 rewrites the ebook container format without touching the text, chapter order, or reflowable layout. Headings, paragraphs, footnotes, and internal links are carried over as-is.
Yes. Drop a folder onto Convertessa or run convertessa ./ebooks/ --to mobi to batch-convert every EPUB in the folder in a single pass.
Yes. Embedded images—including the cover—are carried into the MOBI output. Use the quality setting to control image fidelity when keeping the file size small matters.