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Test regular expressions online, validate matches in real-time, and quickly extract text data.
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Regular Polygon Area Calculator
Enter the number of sides and side length to quickly calculate the area of any regular polygon. Ideal for geometry students and engineering calculations.
Random Decimal Generator
Generate random decimals with a specified range, decimal places, and quantity. Ideal for data analysis, simulation experiments, and more.
Random Email Generator
Bulk generate random email addresses for testing and sign-ups with custom prefixes and domains.
Chinese D-Series Paper Size Lookup
Look up exact millimeter dimensions for D0 to D6 series paper based on the GB/T 19999-2003 national standard, suitable for book, magazine, and office paper design.
Regular Polygon Area Calculator
Enter the number of sides and side length to quickly calculate the area of any regular polygon. Ideal for geometry students and engineering calculations.
Random Decimal Generator
Generate random decimals with a specified range, decimal places, and quantity. Ideal for data analysis, simulation experiments, and more.
Random Email Generator
Bulk generate random email addresses for testing and sign-ups with custom prefixes and domains.
Chinese D-Series Paper Size Lookup
Look up exact millimeter dimensions for D0 to D6 series paper based on the GB/T 19999-2003 national standard, suitable for book, magazine, and office paper design.
Random Phone Number Generator
Generate random phone numbers by country, carrier, and prefix on demand for development, testing, and data simulation.
When you need to validate complex text patterns but struggle with debugging, our Regular Expression Tester provides an instant feedback solution. This tool parses the regex syntax rules (a symbolic system for describing string patterns) entered by the user, performs pattern matching operations on the test text, and ultimately outputs all substring results that match the rules.
How do I match text containing a period (.)?
Use a backslash to escape it: \. will match a literal period.
What regular expression flags does the tool support?
It supports the standard JavaScript flag set: g (global match), i (ignore case), m (multiline), s (dotall/single line), etc., which can be combined using the flags parameter.
Extremely long text (over 100,000 characters) may cause performance delays. Match results only reflect syntax validity; actual application requires validation against your specific business logic. All data processing is done locally in your browser with no server transmission.
We recommend testing basic patterns first: use \d{3} to match three digits, and \w+ to match consecutive word characters. Add complex qualifiers gradually during debugging to avoid modifying multiple syntax units simultaneously. Common examples include matching dates: \d{4}-\d{2}-\d{2}, and matching Chinese characters: [\u4e00-\u9fa5].
