Fission is a fast, lossless audio editor for macOS made by Rogue Amoeba, built for everyone who needs to trim, split, or join sound files without degrading the original recording.
What is Fission?
Fission is a Mac-native audio editor from Rogue Amoeba — the same team behind Audio Hijack and Loopback — purpose-built for quick, non-destructive editing of audio files. Unlike professional digital audio workstations, it stays out of your way: you open a file, make your cuts, and save. No projects, no busses, no bounce menus. What sets it apart from most editors is its commitment to lossless saving — when you edit an MP3 or AAC file, Fission re-encodes only the portions you actually changed, leaving everything else untouched at its original quality.
I keep it in my Dock because it handles the unglamorous audio work that a DAW turns into a fifteen-step ordeal: chopping a podcast intro, removing a dead section at the end of a recorded call, or splitting a long interview into chapter files. It opens nearly instantly on Apple Silicon and does the job before I've even thought about reaching for GarageBand.
What does Fission do best?
Fission's strongest suit is lossless editing — the ability to cut MP3, AAC, Apple Lossless, AIFF, WAV, and FLAC files without re-encoding and degrading audio quality. This is the one thing editors like Audacity can't promise on compressed formats.
Beyond losslessness, the workflow is genuinely fast. The waveform renders immediately, the selection handles snap to silence or a custom threshold, and the keyboard shortcuts are exactly what you'd expect from a native Mac app. Batch-splitting files with chapter markers is handled cleanly, which makes it invaluable for podcast producers or audiobook editors who need to slice long recordings into numbered tracks without babysitting a script.
- Lossless MP3/AAC cutting — only re-encodes edited regions
- Instant waveform rendering — no import or analysis lag on large files
- Chapter and marker support — split on chapter markers in one click
- Format conversion — transcode between MP3, AAC, AIFF, WAV, FLAC, and Apple Lossless
- Volume normalization — smart gain adjustments without touching dynamics
- Tag editing — ID3 and metadata editing baked in, no separate tagging app needed
How much does Fission cost?
Fission is a paid app sold directly from Rogue Amoeba's website. There is a free trial that lets you evaluate the full feature set before buying — the only limitation is a reminder to purchase. Rogue Amoeba does not publish Fission on the Mac App Store, so the license you buy from rogueamoeba.com is what you install. Licenses are perpetual, and the company has a long track record of free updates within a major version.
Given what it replaces — third-party command-line tools, import-and-export cycles in Logic Pro, or the constant re-encoding penalty in other editors — the one-time cost pays for itself quickly if you edit audio more than occasionally.
Who should use Fission?
Fission is the right tool for podcasters, journalists, musicians, and developers who work with audio regularly but don't need a full multitrack DAW. If your editing session looks like "open file → find the cough → delete it → save," Fission is faster than any alternative I've found on macOS.
It is not the right fit if you need multitrack mixing, plugin support, or spectral repair. For those tasks, reach for Logic Pro, Adobe Audition, or even the free Audacity. Fission is resolutely single-track, and that constraint is part of why it's so fast.
What are the best Fission alternatives?
The closest native Mac alternative for quick editing is GarageBand, which is free but forces you into a project paradigm and re-encodes everything on export. Audacity is cross-platform, deeply capable, and free — but it re-encodes lossy files on save and its interface feels like it was designed in a different decade. For lossless MP3 editing on Windows, MP3DirectCut fills a similar niche but has no Mac version. At the pro end, Logic Pro and Adobe Audition do everything Fission does and far more, but they cost significantly more and take considerably longer to open for a thirty-second edit.
If you're a Rogue Amoeba customer already using Audio Hijack to capture audio, Fission becomes the obvious next step for cleaning up those recordings — the two apps share a workflow philosophy and even a waveform display aesthetic.
How does Fission compare to Audacity?
Audacity is free, cross-platform, and multitrack; Fission is paid, Mac-only, and single-track. The decisive difference for many users is lossless editing: Fission can trim an MP3 and save it without touching the untouched portions; Audacity decodes the entire file and re-encodes on export, introducing a new generation of compression artifacts. For destructive, quality-preserving edits on compressed audio, Fission wins. For complex noise reduction, multitrack mixing, or spectral analysis, Audacity wins. I keep both installed and reach for Fission first.
