Diff Checker: Text Comparison Tool
Paste the original text on the left and the modified version on the right to instantly see which lines were added, removed, or left unchanged. Great for comparing code, config files, API responses, or any plain text. Everything runs locally in your browser — nothing is uploaded anywhere.
Frequently asked questions
Is my text uploaded anywhere?
No, everything runs locally in your browser with JavaScript; nothing is sent to a server.
How are the differences calculated?
The tool compares text line by line using the longest common subsequence (LCS) algorithm, the same general approach used by tools like git diff, to find the minimal set of added and removed lines.
Can I compare source code?
Yes, it works with any plain text: code, JSON, XML, logs, config files, or regular paragraphs.
What do "ignore case" and "ignore whitespace" do?
When enabled, two lines that only differ in letter case or in extra whitespace are treated as identical, which is useful when those differences don't matter to you.