Local-first · open source · v0.3.10 for macOS, Windows and Linux
Compare anything. Understand what changed.
Drop two files, folders, images or clipboard contents. TwinScope picks from sixteen engines by looking at what you gave it, and shows you what actually changed — not a wall of red and green.
Free and MIT-licensed · no account · no telemetry · one network call, off by default
users-v2.3.json ↔ users-v2.4.json
GIF · press play
Sixteen engines
The right diff for the thing you dropped
Type detection picks the engine. You can always override it — and every engine explains what it did.
TXTText & code
Side-by-side, unified and inline. Edited lines pair up and are marked word by word instead of appearing as unrelated deletes and adds. Long unchanged runs fold. Syntax highlighting and ⌘F search.
A structural comparison, not a line diff — reformat a file and nothing changes. Arrays match by identity, objects compare as key sets, type changes get their own row, and five layouts including a tree.
YAML and XML, CSV as a grid, dependency manifests and lockfiles, OpenAPI contracts and HAR captures, .env and Kubernetes config with secrets masked, saved web pages, PDFs, git refs, screenshot suites, and a windowed mode for files too large to load.
Drag them in, pick them from disk, or paste with ⌘V. Clipboard images spill to a temp file automatically.
2
Press ⏎
Detection resolves the pair to an engine and says which one. Comparisons run off the UI thread and can be cancelled mid-flight.
3
Read, then share
Counts first, detail second. Step through changes with ⌥↑⌥↓, then export an HTML report, Markdown, or a patch.
Privacy is the product
Your files never leave your machine
There is no account, no telemetry, and not even an opt-in crash reporter. TwinScope makes exactly one network call, and it is off by default: an update check that asks GitHub for the latest version number and tells you. It never downloads or installs anything. This website ships no analytics and no third-party requests at all, which you can verify in your browser’s network panel.
✓Stored: paths, sizes, engine, options and summary counts, in a local SQLite file
✕Never stored: file contents — main strips them itself rather than trusting the caller
✓The renderer is sandboxed, context-isolated, and cannot reach fs
✕No uploads, no cloud sync, no “anonymous usage statistics”
✓Exports are written only when you ask, to the path you choose
Keyboard first
Every mouse action has a key
One registry drives what fires, what the Settings grid lists, and what the palette offers — so the app can never document a key it does not have. Press ⌘K and type.