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Tools / Text diff checker

Text diff checker

Uses a longest-common-subsequence diff, so inserting one line reports one insertion rather than marking everything after it as changed. Works entirely in your browser, which matters when the text is a contract or a config file.

Runs entirely in your browser

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About this tool

Compare two blocks of text and see exactly which lines were added, removed or changed. This is the fast way to spot what differs between two versions of a document, a config file, or a piece of copy without reading both line by line.

It uses a longest-common-subsequence diff — the same class of algorithm behind developer diff tools — so inserting a single line is reported as one insertion, rather than marking everything after it as changed. That precision makes the real differences obvious instead of drowning them in noise.

The comparison runs entirely in your browser, which matters when the text is a contract, a credential file or anything else you would not want to paste into a remote service. Use it to review edits, verify a change, or find the one line that differs between two nearly identical files.

Frequently asked questions

What does the diff show?
The lines that were added, removed or changed between two blocks of text, so you can see exactly what differs between two versions.
Why is the longest-common-subsequence approach better?
It recognises that inserting one line only adds one line, rather than treating everything after it as changed, so the differences it highlights are the real ones.
Is my text uploaded?
No. The comparison runs in your browser, which is important for contracts, config files and other sensitive text.
Can I compare code and config files?
Yes. It is line-based, so it works well for code, configuration and any text where line-level changes matter.
Does it compare word by word or line by line?
It compares line by line, identifying which lines differ between the two inputs.

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