Text Diff Checker
Compare two texts and highlight the differences line by line.
About Text Diff Checker
This online text comparison tool highlights the differences between two texts line by line: removed lines are marked red, added lines green. It is the fastest way to compare two versions of a configuration file, contract draft, code snippet, translation, or log file — paste both texts and the diff renders instantly as you type.
Unlike code-platform diffs, this tool accepts any plain text: legal documents, JSON payloads, CSV exports, essay revisions, or message threads. Writers use it to spot editorial changes; developers to verify generated files; operations teams to compare configuration drift between environments; translators to check what changed in a source document.
The comparison runs entirely in your browser with a standard longest-common-subsequence line algorithm — the same approach as git diff. Nothing is uploaded, so confidential contracts, private keys, or internal documents are safe to compare here.
Frequently Asked Questions
How large can the texts be?
Texts of several megabytes compare in well under a second. For best readability with huge files, compare the relevant sections instead of entire logs.
Does it compare word-by-word within lines?
It highlights whole changed lines, matching how git and code review tools present diffs. This keeps output readable even for heavily edited documents.
Is my text uploaded to a server?
No. The diff algorithm runs in JavaScript in your browser. No data is transmitted or stored anywhere.