About Diff Checker
Paste two versions of anything - a config file, a query, a paragraph - and see the additions and removals marked inline, with a count of each.
Lines or words
Line mode is what a code review shows: a changed line reads as one removal and one addition. Word mode narrows it to the words that actually differ, which is far easier to read when a long line changed in one place, or when comparing prose.
Ignoring noise
Ignore whitespace hides reindentation and trailing spaces, which is useful after a formatter has been run. Ignore case helps when comparing text that has been through a system that normalises capitalisation. Both change what counts as a difference, so turn them off before concluding two files are the same.
Comparing files safely
The two texts are compared in the page and never sent anywhere, which matters because the things people most often need to diff - config files, environment settings, query results - are exactly the things that should not be pasted into someone else server.
Frequently asked questions
- Why do two lines that look identical show as changed?
- Usually invisible characters: trailing whitespace, tabs against spaces, or Windows line endings against Unix ones. Turning on ignore whitespace will confirm it quickly.
- Can it produce a patch file?
- Not yet. The output is a readable comparison rather than a unified diff that git apply would accept.
- Is there a size limit?
- No hard limit, but comparing two very large files word by word is heavy work for a browser. Switch to line mode if a large comparison feels slow.