Text Diff Checker: User Guide
Learn how to compare texts effectively | Updated May 2026
Getting Started
- Paste text into the two text areas — Original (left) and Modified (right)
- Click Compare (or press Ctrl+Enter) to see the diff
- View results side by side with color-coded changes
Understanding Diff Results
- Green lines — Added content (present in modified but not original)
- Red lines — Removed content (present in original but not modified)
- White lines — Unchanged content (same in both texts)
- Line numbers are shown on the left of each column
Keyboard Shortcuts
- Ctrl+Enter or Cmd+Enter — Run comparison
PRO Features
The free version supports comparing texts up to 500 lines. Upgrade to PRO to unlock:
- Unlimited text length — Compare files of any size
- File upload — Drag & drop files directly
- Patch export — Export unified diff format
PRO is a one-time purchase via the PRO Bundle ($19.99) — one key unlocks all 10 tools.
FAQ
What algorithm does the diff checker use?
It uses the Longest Common Subsequence (LCS) algorithm for line-level diff, with character-level diff for changed lines.
Is my text uploaded to any server?
No. Everything runs in your browser. No upload, no tracking, no server.
Can I compare files?
Yes, PRO users can drag & drop files directly into the text areas. The free version supports manual paste only.
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