What is a diff checker?
A diff checker compares two versions of text and highlights what changed. Added content appears in green, removed content in red, and unchanged content stays normal. Developers use diffs to review code changes, but the same tool works for documents, configs, AI outputs, and any plain text.
What's the difference between side-by-side and unified view?
Side-by-side shows the original text on the left and the modified text on the right, each with its own highlights. Unified view merges both into a single panel with + and - prefixes, similar to GitHub or Git diffs. Use side-by-side for parallel reading; use unified for a compact, changelog-style view.
When should I use line-by-line vs word-by-word diffing?
Line-by-line diffing works best for code, configs, logs, and multi-line documents where changes happen per line. Word-by-word diffing is better for prose, emails, or AI-generated paragraphs where edits are small word-level tweaks within the same line.
Is my text sent to a server?
No. All comparison runs entirely in your browser. Your original and modified text never leave your device, so you can safely compare proprietary code, internal documents, or sensitive AI outputs.
Can I compare AI-generated text versions?
Yes. Paste an original AI response and a revised version to see exactly what changed between prompts or model runs. Word-by-word mode is especially useful for spotting subtle rewrites in chatbot outputs.
Is this diff tool free?
Completely free with no limits on text length or number of comparisons. No account, no email, no watermarks. Just paste your text and compare instantly.
