Text Diff Checker
Compare two blocks of text with a clean unified diff view — line numbers from both sides, color-coded add (green) and remove (red) lines, optional case-insensitive and whitespace-insensitive comparison.
11The quick brown fox2- jumps over the lazy dog.3- This line is removed.2+ leaps over a sleepy dog.43Same line in both.4+ A new line added here.55Apple6- Banana6+ Blueberry77Cherry
What powers the Text Diff Checker
LCS-based line diff (same algorithm as git diff)
Unified view with both line numbers shown
Color-coded — green added, red removed, plain unchanged
Ignore-case toggle
Ignore-whitespace toggle
Live diff updates as you edit
Add/remove/unchanged line counts
Why the Text Diff Checker is different
Browser-native
The Text Diff Checker runs entirely in your browser. Input is processed locally — never uploaded, never logged, never cached anywhere outside your device.
No artificial limits
No daily quotas, no character ceilings, no "upgrade for more" walls. Every feature is the complete feature — the same on the first use as the thousandth.
Production-grade quality
Built to the same engineering bar as paid SaaS tools — accurate algorithms, audited logic, responsive design and accessibility-tested interactions.
Common use contexts
- Comparing two versions of a config file or document
- Reviewing changes between two AI-generated drafts of the same prompt
- Spotting subtle differences in code snippets pasted from two places
- Checking if a copy-pasted block matches the original exactly
Private and secure
Zero upload
All processing happens in your browser. Input is never transmitted, logged or cached.
Works offline
Once the page loads, the tool runs without an internet connection. No network calls happen during use.
No tracking
No accounts, no cookies for tool state. Only aggregate analytics count visits at the page level.