Compare two texts and see differences highlighted line by line — free, private, no signup.
Paste the original version in the left box and the changed version in the right box.
The tool highlights added lines in green and removed lines in red. Unchanged lines are shown in grey.
Use the summary stats to see how many lines were added, removed, or unchanged at a glance.
A diff checker compares two versions of text and highlights what changed — what was added, removed, or kept the same. It's widely used by developers, writers, and editors to track changes between versions.
Yes. Paste any code — JavaScript, Python, HTML, CSS, or any other language. The diff is done line by line, making it easy to spot exactly what changed.
No. The comparison runs entirely in your browser using JavaScript. Your text never leaves your device.
It uses a line-based longest common subsequence (LCS) algorithm — the same fundamental approach used by Git and most version control systems.