Diff Checker
Compare any two texts side by side and see differences highlighted instantly — added lines in green, removed lines in red, unchanged lines shown normally. Works for code, JSON, YAML, configuration files, documents, and any plain text. All comparison runs in your browser with zero server communication.
How to Use the Diff Checker
- 1
Paste the original text
Paste the original or older version of your text in the left panel.
- 2
Paste the modified text
Paste the modified or newer version in the right panel.
- 3
Review the diff
Lines only in the left panel (removed) are highlighted in red. Lines only in the right panel (added) are highlighted in green. Matching lines appear normally.
- 4
Scroll through changes
Scroll through the output to review all changes. Use the summary to get an overview of how many lines changed.
Key Features
Private
Your code and config files never leave your browser — safe for proprietary content and credentials.
Color-Coded
Green for added lines, red for removed lines, neutral for unchanged — instantly scannable.
Instant Diff
Diff is computed in real time as you type in either panel.
Pro Tips
For large diffs, focus on the colored lines and skip the gray (unchanged) lines — your eye naturally goes to the changes.
Use the line count summary to get a quick overview before diving into the details.
This tool uses line-level diff — for prose documents where you want to see changed words, use a word diff tool instead.
Privacy Note
All processing in this tool runs entirely in your browser — no data is transmitted to any server. Your input is never logged, stored, or shared. This tool is free to use with no account or registration required.
Frequently Asked Questions
Related Developer Tools
Your input is processed locally in your browser and is never stored, transmitted, or shared with any server. See our Privacy Policy.