AIAZHHow To Use
- Paste Texts — Paste your original text in the left panel and changed text in the right panel. No server upload — everything processes locally in your browser.
- Choose Granularity — Select line, word, or character comparison level depending on how detailed you need the diff to be.
- Compare — Click the "Compare" button to run the Myers diff algorithm and see differences highlighted instantly.
- Review Results — Added lines show in green, removed in red. Toggle ignore whitespace or case options for cleaner output.
- Keep It Private — Your text never leaves your browser. Close the tab and it's gone — no server ever saw it.
Frequently Asked Questions
What is a text diff checker online free tool?
A text diff checker online free tool compares two blocks of text and highlights differences line by line, word by word, or character by character. It uses the Myers diff algorithm — the same algorithm Git uses — to show exactly what was added, removed, or changed between two versions.
Can I compare text side by side?
Yes. The diff tool side by side view shows your original text on the left and changed text on the right, with differences highlighted in both panels for easy comparison.
What comparison modes are available?
The tool supports line-level, word-level, and character-level comparison. You can also toggle ignore whitespace and ignore case options to focus on meaningful changes.
Is my text data kept private?
Yes. All comparison processing happens locally in your browser. Your text is never uploaded to any server or stored anywhere.
Can I share the diff results?
Yes. You can generate a shareable URL that encodes both texts and their comparison results, making it easy to send diffs to collaborators without any account or server storage.
Myers Diff Algorithm
Same algorithm used by Git for precise line-by-line comparison with split and unified views.
Word & Character Granularity
Compare at word level or character level to pinpoint exact changes within lines.
Ignore Whitespace & Case
Toggle options to ignore whitespace changes or case differences for cleaner diffs.
Side-by-Side & Unified Views
Switch between split view and unified diff view for different comparison perspectives.
Share via URL
Generate a shareable link to send diff results to collaborators without any account.
100% Private & Secure
All comparison happens in your browser. Your text never leaves your device.
Free Online Text Diff Checker — Compare Text Online
Our text diff checker online free tool compares two blocks of text and highlights every difference at the line, word, or character level. Whether you need to compare text online for code reviews, document edits, or configuration changes, this text comparison tool gives you instant visual feedback. Added lines appear in green, removed lines in red, and you can switch between split and unified diff views for the perspective that works best for your workflow.
Diff Tool Side by Side — Split & Unified Views
The diff tool side by side view displays original and changed text in parallel panels, making it easy to spot differences at a glance. Switch to unified view to see a single combined output with +/- markers. Both views use the Myers diff algorithm — the same algorithm used by Git — ensuring accurate and efficient comparison even for large texts. This diff tool side by side approach is ideal for comparing code revisions, document drafts, and configuration files.
How the Diff Algorithm Works
The Myers diff algorithm finds the shortest edit script between two texts by computing the longest common subsequence. Lines that exist in the original but not in the changed text are flagged as removed. Lines that exist in the changed text but not in the original are flagged as added. The algorithm runs efficiently in your browser — no text is uploaded to any server, making this safe for comparing sensitive code, confidential documents, or proprietary configuration files.