Text Diff Checker
Paste an original and a modified text to see line-by-line differences, with the changed words highlighted inside each changed line.
How to use
- Paste the older version into Original and the newer version into Modified.
- Read the result: red lines were removed, green lines were added, and the stronger highlight marks the words that changed inside a line.
- Switch between Split and Unified views. Turn on Only changes to collapse long unchanged stretches.
- Use Ignore case and Ignore whitespace to hide differences that do not matter to you.
- Copy or download the result as a unified diff, where each line starts with +, - or a space.
Example
Input
Original: apple banana cherry Modified: apple blueberry cherry date
Output
apple -banana +blueberry cherry +date
Common use cases
- Checking what changed between two versions of a configuration file, query or document.
- Comparing API responses before and after a change.
- Reviewing edits to copy, logs or generated output.
- Verifying that a refactor or export produced identical text.
Common mistakes
- Swapping the two panels. Original is the baseline, so additions appear green only when they are in Modified.
- Seeing differences that are only whitespace or line endings. Turn on Ignore whitespace, or check for tabs versus spaces.
- Expecting moved lines to be recognized as moves. A moved line shows as removed in one place and added in another.
- Comparing text that differs in letter case without turning on Ignore case.
Frequently asked questions
How does the comparison work?
The texts are compared line by line using the Myers diff algorithm, the same family of algorithm used by Git. Inside lines that were changed, the words are compared again to highlight exactly what differs.
Are different line endings treated as differences?
No. Windows (CRLF), Unix (LF) and old Mac (CR) line endings are all read as line breaks, and a final newline at the end of the text is ignored.
What happens with very large or very different texts?
Comparison runs in your browser. When two texts differ in more than a couple of thousand lines, the changed region is shown as removed lines followed by added lines instead of a fine-grained match, and the page tells you so.
Is my text uploaded anywhere?
No. Both texts are compared entirely in your browser and are never sent, logged or stored.