Why Use This Tool
Manually comparing two files is error-prone and tedious. A diff checker instantly shows exactly what changed, making it easy to review edits, spot unintended changes, and understand the evolution of documents or code.
Text Diff Checker
Free online text diff checker. Compare two blocks of text and highlight the differences line by line. Useful for code reviews and document comparison. — runs 100% in your browser, client-side only. No data is sent to any server. Free to use, no account required.
Free
Client-Side
No Login
No Storage
How to Use the Text Diff Checker
What is a Text Diff Checker?
A diff checker compares two versions of text and highlights the differences — added lines (green), removed lines (red), and unchanged lines. The underlying algorithm is LCS (Longest Common Subsequence), the same algorithm used by git diff and most code review tools. CipherKit's diff checker adds inline character-level highlighting within changed lines.
When to Use It
Use a diff checker when comparing config file versions, reviewing code changes before commit, finding differences between API responses across environments, or auditing document modifications.
Who Should Use It
Developers, reviewers, auditors, and support engineers comparing versioned outputs.
How to Use the Text Diff Checker
- Paste original text on the left and updated text on the right
- Run comparison and inspect line-level plus inline changes
- Jump across edits with the minimap
- Copy reviewed output for commit notes or incident reports
Security note
For private code or credentials, prefer local client-side diffing and avoid server-stored paste services.
Common Uses
- Comparing two versions of a configuration file or code snippet
- Reviewing changes in documents before accepting them
- Finding differences between API responses across environments
- Comparing original vs modified text to audit changes
Frequently Asked Questions
What algorithm does this diff checker use?
CipherKit uses LCS (Longest Common Subsequence), the standard algorithm for diff computation. It finds the longest sequence of lines that appear in both texts in the same order, then marks everything else as added or removed. This is the same approach as git diff.
Can I compare code files?
Yes. Paste any text — code, JSON, YAML, config files, prose — into both panels. For file comparison, use the upload button to load files directly without copy-pasting.
What does the gutter bar on the right show?
The gutter bar is a proportional minimap of the entire diff. Red and green marks show where changes are located relative to the full document length. Click anywhere on the gutter to jump to that position.