Text Diff
Original text A
Changed text B
Diff
Type in both panes — the diff updates live

Online Text Diff Checker

Paste the two versions into the left and right panes and the page computes a line-level diff as you type, colour-coding added, removed and modified content. It suits two configs, two revisions of a file, two log excerpts, or a change someone sent you.

The comparison runs entirely in your browser; the text is never uploaded.

Features

How to use

  1. Paste the original text into "Original text A" on the left.
  2. Paste the updated text into "Compared text B" on the right.
  3. Choose unified view or side-by-side view above.
  4. Toggle "Case sensitive" and "Ignore whitespace" to suit the comparison.

FAQ

What do the colours in the result mean?

A green background marks added lines, a red background marks removed ones, and uncoloured lines are identical on both sides. Changed words within a line are highlighted more strongly so you can find them inside long lines.

Can it compare binary files?

No. This is a line-level text comparison; binary data needs a dedicated hexadecimal diff tool.

Will very large texts be slow?

The algorithm scales with the number of lines, and anything up to a few thousand lines is effectively instant. With tens of thousands of lines and very large differences the browser may briefly stutter, so it is worth trimming to the section you actually need to check.

Feedback

This site is front-end only — no backend, no accounts — so feedback goes to GitHub Issues, Discussions, or email.

Paste it into the issue or email to help track it down — it never includes anything you typed

Also: Browse existing issues · Email feedback (no GitHub account needed): 278975598@qq.com