OneTool

Diff Checker

Spot additions and deletions between two text versions instantly.

Line diff

line one
-line two
+line 2
line three
+line four

What is this tool?

A diff shows how one text changed into another. This tool compares line-by-line using a longest-common-subsequence approach and highlights removed lines in red and added lines in teal — useful for configs, copy edits, and code snippets.

How to use it

  1. Paste the original text on the left and the changed text on the right.
  2. Scan the diff view: “-” removals, “+” additions, unchanged lines plain.
  3. Edit either side to update the diff live.