Frequently asked questions

SeamDiff is $9.99 as a one-time purchase on the Mac App Store. No subscription, no recurring fees, no hidden costs.

Not at the moment. The Mac App Store doesn't support time-limited trials for paid apps. SeamDiff is $9.99 once — if you're not happy with it, Apple's standard refund policy applies.

Yes. A single App Store purchase covers all your personal Macs signed in with the same Apple ID — that's standard Mac App Store licensing.

SeamDiff requires macOS 13 Ventura or later. It works on macOS 13, 14 Sonoma, and 15 Sequoia.

Yes. SeamDiff is a universal binary — it runs natively on both Apple Silicon (M1, M2, M3, M4) and Intel Macs with no Rosetta translation.

Any plain text file. Syntax highlighting works for all major languages — JavaScript, TypeScript, Python, Swift, Go, Rust, Ruby, PHP, JSON, YAML, Markdown, HTML, CSS, and many more — powered by the Monaco editor.

Binary files (images, compiled executables, etc.) cannot be diffed and will show a notice instead.

Yes. Drag two folders onto the SeamDiff window (or pick them with the folder icon) and you'll get a full file list showing everything that was added, removed, or modified. Click any file in the list to open it in the diff editor. You can filter by change type to focus on what matters.

Yes. Drop a file onto the left or right panel to load it on that side. Drop two files at once and SeamDiff places one on each side automatically. Drop a folder to open the folder diff view. It's the fastest way from "I have two files" to "I can see the diff".

Yes. Hover any diff block and merge arrows appear in the gutter — click ← to copy the right side's version into the left file, or → to do the reverse. Each block can be merged independently, and every merge can be undone per side. When you're done, hit Save in the path bar to write the result to disk.

Yes — Git support is built in. Open any Git repository and you get three tabs:

Changes — every file modified, added, or removed since the last commit. File list on the left, diff on the right. Toggle between side-by-side and unified view.

Compare — pick any two branches, tags, or commits and get a full file-by-file diff. Click any file to open the before-and-after in Monaco.

History — the full commit log across all branches with a colour-coded branch graph, ref chips, and PR badges. Click any commit to see its files, then drill into any file for the full diff.

Yes. SeamDiff follows your macOS system appearance automatically — switch your Mac to dark or light mode and SeamDiff updates instantly. You can also lock it to either mode in Settings, independent of your system preference.

Yes. In Settings you can adjust the hue and opacity of the added and removed highlight colours independently. The changes apply live so you can dial in exactly what works for your eyes.

No. SeamDiff is completely offline. Your files never leave your Mac — all diffing happens locally. See our Privacy Policy for full details.

Yes. SeamDiff runs in the macOS App Sandbox and is distributed exclusively through the Mac App Store. It only accesses files you explicitly open via the file picker.