Text Diff Checker
Compare two texts and see exactly what changed. Line-by-line diff with added/removed highlighting. All processing in your browser.
How to Use the Text Diff Checker
- 1. Paste your original text into the left panel.
- 2. Paste your modified text into the right panel.
- 3. The diff updates automatically — green lines are additions, red lines are deletions.
- 4. Toggle "Show unchanged lines" to focus only on changes.
Line-by-Line Comparison
Uses the Myers diff algorithm — the same algorithm used by Git — to produce minimal, accurate diffs between any two text inputs.
Code & Text Support
Works with source code, configuration files, markdown, plain text, JSON, and any other line-based content you need to compare.
Instant Diff, No Upload
All comparison happens locally in your browser. Your files and text are never sent to a server, ensuring complete privacy.
Diff Statistics
See at a glance how many lines were added, removed, and unchanged. Great for reviewing pull requests, config changes, and document revisions.
Frequently Asked Questions
What diff algorithm does this use?
This tool uses the Myers diff algorithm, which finds the minimal edit distance between two texts. It's the same algorithm used by Git and most modern version control systems.
Can I compare code files?
Yes — paste the content of any text-based file: source code, JSON, YAML, Markdown, HTML, CSS, etc. The diff is line-based, so it works best with structured text.
Is my data private?
Completely. All processing runs in your browser using JavaScript. Nothing is uploaded to any server. You can use this tool completely offline once the page is loaded.
What do the colors mean?
Green lines (prefixed with +) are additions present in the Modified text. Red lines (prefixed with -) are deletions that only exist in the Original text. Neutral lines are unchanged.