Text Diff Checker

Compare two texts line by line

Paste two versions of a text — a document, some code, a config file, an email draft — and this tool highlights exactly what changed between them. Green lines were added; red lines were removed; unchanged lines stay neutral. It uses a proper longest-common-subsequence diff, the same approach version-control tools use, so it aligns matching lines correctly instead of just comparing position by position.

What it's good for

• Spotting edits between two drafts of writing.
• Comparing two versions of a snippet, config, or list.
• Checking what a copy-paste or find-and-replace actually changed.

FAQ

Is this a word-level or line-level diff?

Line-level — it compares whole lines. If a single word changes in a long line, the whole line shows as removed-and-added. For prose, splitting sentences onto separate lines gives a finer comparison. Everything runs locally in your browser.

Is this text diff tool free, and is my text private?

Yes — it's free with no sign-up, and the comparison runs entirely in your browser. Neither version of your text is uploaded or stored, so it's safe to compare confidential documents or code.

What do the green and red lines mean?

Green lines were added in the second text, and red lines were removed from the first. Lines that appear in both stay neutral. This lets you see at a glance exactly what was inserted, deleted, or left untouched.

How does it know which lines match up?

It uses a longest-common-subsequence diff — the same algorithm version-control tools rely on — to align matching lines even when content is inserted or deleted in the middle. That's more accurate than comparing the two texts position by position.

Can I use it to compare code?

Yes. It works well for snippets, config files, and lists where each line is meaningful. Just paste the two versions and it highlights every added and removed line, all without sending your code anywhere.

Does it work on mobile?

Yes. The tool is responsive and runs in any mobile browser, so you can compare two texts on a phone or tablet without installing anything.