How does the line-by-line comparison work?

The tool splits both texts into lines and finds the longest common subsequence between them, which is the same core idea used by most diff tools. Lines that match stay unchanged, lines only in the original are marked removed, and lines only in the changed text are marked added.

What does "Ignore whitespace" do?

It trims each line and collapses repeated spaces before comparing, so differences that are purely about spacing — extra spaces, tabs, or trailing whitespace — won't show up as changes.

Can this compare code or does it only work on prose?

It works on any plain text, including code, config files, or CSV rows — it compares line by line regardless of content, so it's useful for spotting changes in source files as well as paragraphs.

Is my text uploaded anywhere?

No. Everything runs locally in your browser with JavaScript — neither the original nor the changed text is ever sent to a server.

TEXT DIFF CHECKER

Compare two blocks of text and see exactly what changed, line by line. Nothing leaves your browser.

Original

Changed

Diff result

The quick brown fox

jumps over the lazy dog

jumps over the sleepy dog

Every day is a good day

A new final line.

The end.

Added: 2Removed: 1Unchanged: 3

How to compare two texts

1
Paste the original text into the left box and the changed text into the right box.
2
Optionally toggle "Ignore whitespace" or "Ignore case" to skip trivial differences.
3
Review the diff below — removed lines are struck through in red, added lines are highlighted in green, and unchanged lines stay muted.

Questions

How does the line-by-line comparison work?: The tool splits both texts into lines and finds the longest common subsequence between them, which is the same core idea used by most diff tools. Lines that match stay unchanged, lines only in the original are marked removed, and lines only in the changed text are marked added.
What does "Ignore whitespace" do?: It trims each line and collapses repeated spaces before comparing, so differences that are purely about spacing — extra spaces, tabs, or trailing whitespace — won't show up as changes.
Can this compare code or does it only work on prose?: It works on any plain text, including code, config files, or CSV rows — it compares line by line regardless of content, so it's useful for spotting changes in source files as well as paragraphs.
Is my text uploaded anywhere?: No. Everything runs locally in your browser with JavaScript — neither the original nor the changed text is ever sent to a server.