Free Text Diff Online
Compare two texts and see word-level differences. Additions shown in green, deletions in red. All processing in your browser.
The Text Diff tool compares two texts and shows word-level differences, with additions in green and deletions in red. All processing happens in your browser, so neither text leaves your device.
Free online text comparison tool
This text diff tool compares two versions of text and shows exactly what changed at the word level, using a Longest Common Subsequence algorithm to find the comparison that minimizes the number of edits. It is useful for reviewing how a document changed between drafts, comparing two code snippets, tracking edits in a configuration file, or checking that a translation kept the meaning intact. Rather than scrolling two blocks of text and squinting, you get a single merged view that highlights the additions, the removals, and the parts that stayed the same.
The result is color-coded so the changes are obvious at a glance. Words that appear only in the second text are highlighted in green to mark what was added, words that appear only in the first are shown in red to mark what was removed, and everything that is unchanged stays in plain text. Combined with subtle background shading on the changed segments, this makes it easy to see both the nature and the location of each modification, even in a long document with many small edits scattered through it.
All of the comparison runs locally in your browser with pure JavaScript, so the text you are comparing never leaves your machine. That matters when the content is sensitive, such as internal communications, client work, or proprietary code, because nothing is uploaded to a server and no account is required. The tool also handles the kinds of text people actually diff, including code, prose, JSON, and XML, and it adapts to different lengths without any setup, so you can paste two versions and read the changes immediately. No installation or configuration is needed to get started.
How to use this Text Diff tool
- Paste your original text into the "Text A" field above.
- Paste the modified version into the "Text B" field.
- The diff result appears below with additions in green and deletions in red.
- Scroll through the result to see exactly what changed between versions.
FAQ
What is the Text Diff tool?
This tool compares two texts and shows word-level differences, highlighting additions in green and deletions in red using an LCS algorithm.
How does the diff algorithm work?
It uses a Longest Common Subsequence (LCS) algorithm to find the optimal way to transform text A into text B, identifying which words were added, removed, or unchanged.
Is my text data stored anywhere?
No. All comparison happens entirely in your browser using JavaScript. No data is uploaded, stored, or shared with anyone.
Does it work with large texts?
The algorithm handles reasonable text sizes well. For very large files, the comparison may take a few seconds depending on your device's performance.