Text Diff
Paste the older text on the left and the newer text on the right. The comparison is line by line. It does not highlight a changed word inside a line. Large pastes fall back to comparing line 1 to line 1, then line 2 to line 2.
Limit: 400 KB on each side. Ctrl or Cmd+Enter compares.
Result
How the comparison works
The tool splits each box at line breaks. It then finds a line-by-line alignment: shared lines stay unmarked, lines only on the right are added, and lines only on the left are removed. A line that changed in the middle counts as one removal and one addition. That is enough to see a list edit. It is not a word processor track-changes view.
When this tool helps
Use the diff when two versions of a list, a config, or a short script sit in front of you, and you want the line changes without opening a repository. Copy writes a plus/minus listing you can paste into a note. Each side can stay in this browser so you can come back. The page does not connect to git.
Questions
Why did one edited word become two lines?
The unit is the whole line. If a line is not identical, the left copy is marked removed and the right copy is marked added.
What happens with a very long paste?
If left-lines times right-lines is large, the tool compares the same row numbers instead of searching for moved blocks. Shorten the texts for a full alignment.
Does the text leave this tab?
No. The comparison runs in the browser.