What is Text Diff Checker?
Text diff tool (diff checker) — compare two texts line by line. Uses the Longest Common Subsequence (LCS) algorithm to compute differences, highlighting additions (green), deletions (red), and modifications. Perfect for code review, document version comparison, config file change checks, and translation alignment. Options to ignore whitespace and case differences. All comparison runs locally in your browser.
Use Cases
- ◆Code review (before/after comparison)
- ◆Document version diffing
- ◆Config file change detection
- ◆Translation text alignment
- ◆API response before/after comparison
How to Use
- 1Paste original text in the left box
- 2Paste modified text in the right box
- 3Review highlighted differences
- 4Copy the diff report
Features
- ✓Line-by-line diff
- ✓Color highlighting
- ✓Ignore whitespace
- ✓Ignore case
- ✓Real-time computation
FAQ
What algorithm does the diff use?
Longest Common Subsequence (LCS) — the same principle as Git diff. Time complexity is O(n×m), so very large files may take a few seconds.
Can I compare code files?
Yes. Works with any plain text: code, JSON, XML, Markdown, etc. Enable "Ignore whitespace" to reduce noise.
Can it ignore case differences?
Yes. Enable "Ignore case" and "Hello" will match "hello" — treated as identical content.
Is my text uploaded anywhere?
No. All comparison runs locally in your browser. Nothing is sent to a server.
Can I compare two files directly?
Paste the contents of each file into the left and right text boxes. Direct file drag-and-drop is planned for a future update.
What do + and - mean in the results?
+ indicates lines added in the right text (green), - indicates lines removed from the left text (red). Same format as Git diff and Unix diff.