Text Diff Checker

A free diff checker that keeps your text private

This tool compares two pieces of text using a real longest-common-subsequence (LCS) algorithm — the same family of algorithm that powers git diff. Because it runs locally in your browser, you can safely compare contracts, configuration files, source code, essays and anything else without it ever leaving your computer.

How to compare two texts

• Paste the original on the left and the changed version on the right.
• Choose Side-by-side to see both versions aligned, or Unified for a single git-style +/- view.
• Keep Word-level highlight on to see exactly which words changed inside an edited line.
• Use the ignore options for case or whitespace when you only care about meaningful changes.
• Hit Copy unified diff to grab a patch-style diff for a commit message, ticket or email.

Line diff vs word diff

A line diff tells you which lines were added or removed. Word-level highlighting refines that: when a line was merely edited, the unchanged words stay neutral and only the changed words are tinted, so a small fix reads as a small fix instead of a delete-plus-add of the whole line.

Comparing code and config

The diff is language-agnostic and preserves indentation, so it works for Python, JavaScript, JSON, YAML, SQL, Markdown or plain prose. When a change is only reformatting, switch on ignore all whitespace to suppress the noise and surface the lines that actually changed.