diff-checker
Paste two versions of text, config, or code to see what changed — split or unified view, word or character precision. Click a line or a block to resolve it right there in the diff, without touching what you pasted. Everything runs in your browser; nothing is uploaded.
// how this compares text
// when to use this
- Reviewing two versions of a config file,
.env, or SQL migration before applying one. - Checking what changed in a code snippet pasted over Slack without checking out the branch.
- Comparing generated output (a formatter or codemod result) against the original to sanity-check the transformation.
- Quick spot-check on any two text blobs — logs, JSON responses, API payloads.
For full files or real pull requests, your editor's diff view or git diff handles renames, whitespace-only changes, and binary files better. This tool is for fast in-browser checks, not a replacement for VCS tooling.
// merging: line by line, or a whole block at once
Once a comparison is up, the right column is the result: it shows the new/changed version by default, and clicking a line's left side swaps that one line's display on the right back to the original — clicking its right side undoes that. Use a block's "Use left / Use right for this block" buttons to resolve a whole hunk in one click instead of line by line. This never touches what you pasted above, so you can always compare again from the original two versions — grab the current result with the "copy result" button next to the additions count.
Uses LCS (longest common subsequence) — the same algorithm behind
git diff. Lines that changed are then diffed a second time at word or character precision to highlight exactly what shifted inside the line. Split view shows both versions side-by-side; unified view shows a single column with−and+markers.