Enter text in both boxes and click Compare

🔒 Private by design. The comparison runs entirely in your browser. No text is uploaded, sent, or stored anywhere.

How to Use

1
Paste your texts. Put the original version in the left box and the new version in the right box.
2
Click Compare. The diff view shows all differences line by line. Lines that are only in the original appear red on the left. Lines only in the new version appear green on the right. Modified lines appear in yellow on both sides.
3
Check the summary. The stat line above the diff shows the total number of added and removed lines at a glance.
4
Swap or clear. Click Swap to exchange the left and right inputs. Click Clear to start over.

When to Use a Text Diff

Comparing two versions of a contract or legal document to spot what changed. Checking a revised article against the original before publishing. Verifying that two configuration files that should match actually do. Finding the differences between two lists of values when both are too long to scan by eye.

Worked Example

Original: New: The cat sat. The cat sat. The dog ran. The dog jumped. The bird flew. The fish swam. The bird flew. Diff result: "ran" changed to "jumped", "fish swam" added, order adjusted.

Frequently Asked Questions

What is a text diff tool?

A text diff tool compares two pieces of text and highlights the lines that are different. Added lines appear in green, removed lines in red, and changed lines in yellow. It is useful for comparing two versions of a document, checking what changed in a contract, or spotting differences between a draft and a final version.

Is my text sent to a server?

No. The comparison runs entirely in your browser using JavaScript. Your text is never uploaded or stored anywhere. This makes the tool safe to use with sensitive or confidential text.

What algorithm is used for the diff?

The tool uses a longest common subsequence (LCS) approach to find the minimum set of changes between two texts, the same algorithm used by most diff tools and version control systems like Git.

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