Text Diff Checker

How to use it

Paste the original on the left and the changed text on the right, then Compare. Equal lines are unmarked. Deleted lines are prefixed with a minus and inserted lines with a plus. The comparison is line based, not a character-level patch.

Example

Shared lines stay unmarked. The changed line is a deletion plus an insertion, and the new last line is an insertion. The example input uses a --- separator between the two sides.

alpha
beta
gamma
---
alpha
BETA
gamma
delta

  alpha
- beta
+ BETA
  gamma
+ delta

How it works

The checker uses a longest-common-subsequence comparison for inputs up to 1,500 lines a side, as long as the line product stays within a safe bound. Larger texts are refused so the browser does not freeze. Blank lines count as lines.

Common errors

• Nothing was highlighted The two sides are identical, including blank lines.
• A whole paragraph moved and the diff is noisy The unit is a line. Break long paragraphs into lines if you want a tighter comparison.
• The tool refused the text Each side is limited to 100,000 characters and 1,500 lines.

Limitations

This is not a git-compatible patch and it does not ignore whitespace unless the lines already match. It does not upload either side.

Privacy

The text you paste is processed in your browser. PepsTools does not receive it, store it, or send it to another service.

Questions

Does it compare words inside a line?

No. A changed line is shown as one deletion and one insertion.