Text Diff Checker

Compare two versions side by side and see exactly which lines were added, removed or kept.

About this tool

What actually changed between two versions of a config, a list or a paragraph? This checker computes a real longest-common-subsequence diff — the same technique as git diff — and marks each line as added (green), removed (red) or unchanged, with original line numbers.

How to use it

  1. Paste the original text on the left and the changed text on the right.
  2. Click Compare and read the unified result with per-line numbers.

Good to know

  • Comparison is exact and line-based; trailing spaces count, so trim first with the Text Cleaner if whitespace noise does not matter to you.
  • The precise algorithm handles files up to roughly 2000 × 2000 lines; larger inputs are politely refused instead of freezing your browser.
  • The comparison happens entirely in your browser — nothing is uploaded.