Regex Diff & Compare
Paste two regex patterns to see highlighted line-by-line differences, a change summary, and a similarity percentage. Everything is processed on your device.
Everything runs in your browser. Your data is never sent to our servers.
Example
Example Input
two regex patterns
Example Output
pattern differences highlighted
How to Use
- 1Paste the first regex patterns (A) in the left box and the second (B) in the right box.
- 2Adjust the options if needed (ignore case, whitespace, or empty lines).
- 3Click Compare (or press Ctrl+Enter).
- 4See the highlighted differences, a summary of how many changes there are, and the similarity percentage. Switch between side-by-side / unified / inline views.
About Regex Diff & Compare
Regex Diff & Compare compares two regular-expression patterns line by line so you can see small differences like an added group, flag, or escape.
Useful when refining a pattern and you want to know exactly what changed from the previous version.
FAQ
What is the difference between "diff" and "compare"?
Both are done by the same tool. "Diff" highlights the lines/parts that changed (added/removed), while "compare" shows how similar the two inputs are (similarity percentage + summary). You get both at once here.
Is my data sent to a server?
No. The entire comparison is computed in your browser with JavaScript. Nothing is uploaded, logged, or stored on our servers — safe for sensitive data.