Free Regex Tester Online — Test Regular Expressions Privately
How to Use the Regex Tester
Email and Phone Validation Patterns
Test regex patterns for form input validation — email addresses, phone numbers, postal codes, and URLs. See matches highlighted in real time.
Log Parsing and Data Extraction
Write patterns to extract IPs, timestamps, error codes, or user IDs from log files. Safe to paste real log snippets — nothing is sent to a server.
URL Routing and Path Matching
Test URL patterns for Express.js, Next.js, or Nginx config before deploying. Verify that your routes match the right paths.
Find and Replace in Text
Craft regex patterns for global find-and-replace operations in code editors or scripts. Test against real examples before running.
Frequently Asked Questions
Is it safe to test regex with real log data containing sensitive info?
Yes. BigWow's regex tester runs all matching using the browser's native JavaScript RegExp engine. Your test text never leaves your device.
How is this different from Regex101?
Regex101 processes your input on their servers and may log patterns. BigWow tests entirely in-browser with no server interaction — safe for sensitive data.
What regex flags are supported?
All JavaScript flags: g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode), y (sticky).
Does it support named capture groups?
Yes. The tester uses the browser's native RegExp engine, supporting all modern ECMAScript features including named groups and lookbehinds.