Text Diff Checker
Compare two blocks of text and highlight every addition and deletion.
Compare
Private by design. Everything runs locally in your browser. Your input is never uploaded, logged or stored on a server.
Frequently asked questions
What does this diff checker do?
It compares two blocks of text and marks what was added, removed or left unchanged, using the same longest-common-subsequence approach as version-control diffs.
When should I use word mode instead of line mode?
Use word mode for prose, where a small edit inside a paragraph would otherwise show as a whole changed line. Use line mode for code and config files.
Can I compare two files?
Paste the contents of each into the two panels. Nothing is uploaded either way, so it works for private documents.
Why are two visually identical lines marked as different?
Usually trailing whitespace or a different line ending. Turn on "ignore whitespace" to confirm.
About the Text Diff Checker
Two modes cover different questions. Line mode answers "which lines changed" and is right for code, configuration and logs. Word mode answers "what changed inside this paragraph" and is right for prose, where a line diff would mark an entire rewrapped paragraph as changed.
Ignore-whitespace helps when a file has been reindented or had its line endings converted between CRLF and LF, changes that are real but usually not what you are looking for. Ignore-case helps when comparing output from systems that normalise differently.
The summary counts added, removed and unchanged lines so you can judge the size of a change before reading it.