About the Text Diff Tool
Compare two pieces of text and instantly see what was added, removed, or changed. This free online text diff tool is perfect for reviewing edits, comparing config files, or spotting changes between document versions — all without uploading anything.
Why this tool is useful
- Review edits and spot unintended changes quickly.
- Compare config or code snippets without a full IDE.
- Privacy-first: sensitive text never leaves your browser.
How it works (client-side)
- Paste the original text on the left and the changed text on the right.
- Click Compare to run a line-by-line diff.
- Added, removed, and unchanged lines are highlighted inline.
Frequently asked questions
Does it compare word-by-word or line-by-line?
By default it compares line-by-line, which is ideal for most documents and code. Changes within a line are shown as added/removed lines.
Is there a file size limit?
Performance depends on your device, but documents of tens of thousands of lines compare in well under a second.
Is my text uploaded?
No — the comparison runs entirely in your browser.