Diff Checker
Paste two texts or code snippets and instantly see every addition, deletion, and change — line by line, word by word.
Paste text in both fields above to see the diff.
Supports plain text, code, JSON, HTML, Markdown — anything.
Instant results
Diff runs live as you type. No button to click, no waiting — changes appear the moment you paste.
Private by design
All processing happens in your browser. Your text never leaves your machine — no server, no logs.
Works with any text
Compare code, configs, prose, JSON, HTML, SQL — any plain text. Word-level highlighting on changed lines.
Frequently asked questions
What is a diff checker?
A diff checker compares two pieces of text and highlights the differences between them — lines that were added, removed, or changed. It's an essential tool for developers reviewing code changes, writers comparing document versions, and sysadmins comparing config files.
What's the difference between split view and unified view?
Split view shows original and modified text side-by-side in two columns — easier to read when comparing long files. Unified view shows everything in a single column with + and − prefixes on changed lines, similar to git diff output.
Can I compare code files?
Yes — paste any code directly into the text areas, or use the "Load file" button to read a file from your computer. The diff checker works with any plain text format: JavaScript, Python, JSON, HTML, CSS, SQL, YAML, Markdown, and more.
Is my text sent to a server?
No. The diff algorithm runs entirely in your browser using JavaScript. Nothing is uploaded or stored. You can even use this tool offline once the page is loaded.