Diff Checker

Make both sides comparable first

A line diff reports any byte of difference, so a reindented file or trailing spaces make every line look changed. Put both texts through the same formatter first: the SQL formatter for queries, or the same editor settings for code. For JSON, the JSON diff compares by key and ignores formatting and key order altogether.

Reading the result

An edited line shows as a pair: the old version marked - and the new version marked +. A block that moved appears as a removal in one place and an addition in another, since a line diff has no notion of moving. When one small word changed in a long line, the pair is the whole line; compare those two lines side by side to spot it.

Beyond 500 lines per side, use git diff --no-index old.txt new.txt, which works on any two files, or diff -u old.txt new.txt.

How to use it

1. Paste original and changed text.
2. Choose Compare text.
3. Review or download the prefixed line diff.

Privacy & limitations

Both inputs remain local. The comparison is capped at 500 lines per side to avoid excessive browser memory use.