Diff Checker Online — Compare Text & Code Differences
A diff checker compares two blocks of text or code and highlights every difference line by line. Paste both versions to instantly see what was added, removed, or changed — free and private.
Loading diff…
How to use Diff Checker
- Paste the original text on the left and the changed text on the right.
- Differences are highlighted automatically, line by line.
- Use Swap to reverse the sides, or Clear to start over.
Features
Side-by-side diff
Compare two blocks of text and spot every change instantly.
Line-by-line highlighting
Added, removed, and modified lines are color-coded.
Any text
Compare code, logs, prose, config — anything, not just JSON.
100% private
Your text is compared in your browser and never uploaded.
What is Diff Checker?
A diff checker is a quick way to see what changed between two versions of a file or snippet. It highlights additions, deletions, and edits side by side, which is invaluable for code review, debugging, and proofreading. JSON Reader runs the comparison entirely in your browser.
Related JSON tools
Frequently Asked Questions
Everything you need to know about JSON Reader
Any two blocks of text — source code, logs, essays, configuration, or data. The tool highlights every line-level difference.
Yes. The comparison runs entirely in your browser; nothing is sent to a server.
Yes. Both sides stay editable, so you can tweak the text and watch the diff update.