Diff Checker
Paste two versions of some text to see exactly what was added and removed, line by line. Everything runs locally in your browser — nothing is uploaded.
New to this? Read the Diff Checker guide →
Paste two versions and press Compare.
How to use the diff checker
- Paste the original text on the left and the changed text on the right.
- The result highlights what was added, removed and unchanged, line by line.
- Read it side by side to see exactly what moved between the two versions.
The comparison runs entirely in your browser, so you can safely diff private code, contracts or config without anything being uploaded.
What a diff actually shows
A diff finds the smallest set of additions and deletions that turns the first text into the second, the same idea Git and code-review tools use under the hood. Lines that match are left alone; lines that differ are marked as removed (from the original) or added (in the new version). That makes it easy to spot a single changed character in a wall of otherwise identical text.
Common uses
- Reviewing what changed between two versions of a file or code snippet.
- Comparing a config or environment file against a known-good copy.
- Checking edits to a contract, policy or piece of writing before signing off.
- Spotting accidental changes after a copy-paste or a merge.
Tips
If a diff looks noisier than expected, check for differences in trailing whitespace or line endings, which often show up as changes even when the visible text is identical. Comparing well-formatted text on both sides (for example, pretty-printing JSON first) keeps the diff focused on real changes rather than formatting.
Where you'd use this
Any time two versions of something should be identical and are not: a config file that works on staging but not production, a contract that came back from the other side's lawyer, a translated string file, a log before and after a change.
For example: A deploy fails and the only clue is that the production .env differs from staging. Pasting both reveals a single line: TIMEOUT=30 against TIMEOUT=3000 — a missing zero causing every upstream call to time out.
Frequently asked questions
How do I compare two texts?
Paste the original on one side and the changed version on the other; the tool highlights added, removed and unchanged lines so you can see exactly what differs.
Does it work for code as well as prose?
Yes. A line-by-line diff works for source code, config files, JSON, logs or plain writing — anything text-based.
Is my text uploaded to compare it?
No. The comparison happens entirely in your browser, so you can safely diff private or sensitive files.