What is a Text Diff Checker?
A diff checker compares two versions of text and shows you exactly what changed — which lines were added, which were removed, and which stayed the same. It is the same technology behind code review tools and version control systems like Git.
This tool uses a Longest Common Subsequence (LCS) algorithm to compute a clean line-by-line diff directly in your browser. It is perfect for comparing config files, copy edits, log output, or any two snippets of text.
Common Use Cases
📝 Proofreading
See exactly what an editor changed between two drafts of a document.
⚙️ Config Comparison
Spot differences between environment configs, like staging vs production.
🐞 Debugging Output
Compare expected vs actual output to quickly locate failing test differences.
📋 Data Cleanup
Verify changes after running a find-and-replace or formatting pass.
Frequently Asked Questions
Is my text uploaded to a server?
No. The entire comparison runs locally in your browser, so even sensitive text stays private.
Does it compare word by word?
This tool compares line by line, which is the most common and readable form of diff. You can enable "ignore whitespace" to focus on meaningful changes.