Question 1

How does the text diff tool work?

Accepted Answer

Paste your original text in the left textarea and your modified text in the right. Click Compare and the tool runs a line-by-line diff algorithm in your browser. Added lines appear in green, removed lines in red, and unchanged lines are shown as-is.

Question 2

What algorithm is used to compute the diff?

Accepted Answer

The tool uses the Longest Common Subsequence (LCS) algorithm, which is the same approach used by most diff utilities. It finds the minimal set of additions and removals needed to transform the original text into the modified version.

Question 3

Is this tool good for comparing code?

Accepted Answer

Yes. The diff is line-based, so it works well for comparing source code, configuration files, JSON, YAML, and any structured text. The monospace display keeps formatting intact.

Question 4

Can I copy the diff output?

Accepted Answer

Yes. The Copy diff button exports the diff in unified format, with + and - prefixes on changed lines. You can paste this into a bug report, pull request description, or documentation.

Question 5

Is my text sent anywhere?

Accepted Answer

No. All comparison happens locally inside your browser. Neither the original nor the modified text is ever sent to a server.

Text Diff

Free online text diff tool

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