Your files stay on your Mac.
OPML files store structured outlines — podcast subscriptions, RSS feed lists, and hierarchical notes. Converting to HTML renders that hierarchy as a navigable web page you can open in any browser. Convertessa processes every file locally; nothing is uploaded or sent to a server.
Drag one OPML file or an entire folder into Convertessa. Batch mode processes every .opml file in the folder in a single pass.
Choose HTML from the output list. Convertessa will render the outline structure as nested HTML lists, ready to open in any browser.
Click Convert. Your HTML files appear instantly alongside the originals. No account, no internet connection required.
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.
Convertessa maps the outline hierarchy in your OPML file to nested <ul> lists in HTML, preserving the structure so each item and sub-item is readable in any browser without extra tooling.
Yes. Run convertessa ./folder --to html and Convertessa batch-converts every OPML file in that directory in one pass, writing an HTML file next to each original.
Completely. Convertessa runs offline — files are never uploaded to any server. The conversion happens entirely on your machine.