Regex Validator
Paste a regex pattern to check whether it is valid — complete with the reason if it is invalid and a component breakdown if it is valid. Everything is processed on your device.
Everything runs in your browser. Your data is never sent to our servers.
Example
Example Input
(?<year>\d{4})-(\d{2})Example Output
✓ VALID — 2 groups, 1 named (year)
How to Use
- 1Paste the a regex pattern you want to check into the input box.
- 2If the tool offers extra options (e.g. dialect, flags, or variant), set them as needed.
- 3Click Validate (or press Ctrl+Enter).
- 4Read the result badge — VALID, INVALID, or VALID with a warning — along with the details and the list of issues, if any.
About Regex Validator
Regex Validator tries to compile the pattern with JavaScript's built-in RegExp engine and reports whether the pattern and its flags are valid. When valid, it shows the capture-group count and named groups. It accepts both the /pattern/flags literal and separate pattern + flags.
Useful for testing a pattern before pasting it into code — an invalid flag or unbalanced bracket shows up immediately.
FAQ
Is my data sent to a server?
No. All validation runs in your browser with JavaScript. Nothing is uploaded, logged, or stored on our servers — safe for sensitive data.
How is this validator different from a parser or formatter?
A validator answers one question: is this input correct/valid? It returns a valid/invalid badge with the reason. A parser breaks input into its components, and a formatter tidies its layout. Use a validator when you just need to confirm something is sound before using it.