Regex Tester Online

What is Regex Tester Online?

Regex Tester Online is an online tool for real-time testing and debugging regular expressions. Supports JavaScript regex syntax, highlights matches, shows capture groups. Processing speed <10ms. Suitable for form validation, text extraction, and data cleaning.

FAQ

What is Regex Tester Online?

Regex Tester Online is an online tool for real-time testing and debugging regular expressions. Supports JavaScript regex syntax, highlights matches, shows capture groups. Processing speed <10ms.

What regex syntax is supported?

Supports JavaScript regex syntax: (1) Character classes [abc]; (2) Quantifiers *+?{n}; (3) Groups (); (4) Assertions (?=)(?!); (5) Flags gimuy. Does not support PCRE features like (?P<name>).

Can it test multiple matches?

Yes. With global flag g, shows all matches. Each match displays: (1) Matched text; (2) Start position; (3) End position; (4) Capture group content. Shows up to 1000 matches.

What regex flags are supported?

Supports 6 flags: (1) g global; (2) i case-insensitive; (3) m multiline; (4) s dot matches newline; (5) u Unicode mode; (6) y sticky. Can combine like gi.

What are the use cases?

Suitable for: (1) Form validation (email, phone); (2) Text extraction (URLs, dates); (3) Data cleaning (remove special chars); (4) Log analysis (match error patterns); (5) Code refactoring (batch replace).

Is data uploaded to servers?

No. All matching is done locally in the browser using native JavaScript RegExp object. No internet connection required, protecting privacy.

Does it work on mobile?

Fully supported. Responsive design adapts to phones, tablets, and computers. Works on iOS Safari 12+, Android Chrome 80+.

Are there common regex presets?

Provides 20+ common presets: (1) Email validation; (2) Phone (China); (3) URL matching; (4) IPv4 address; (5) Date (YYYY-MM-DD); (6) Chinese characters. Custom preset saving supported.