What is a Regex Tester?

A regex tester allows you to validate regular expressions online and check how patterns match strings instantly.

How do I test a regex pattern online?

Enter your regex in the input box and provide a test string. Click 'Test Regex' to see if your pattern matches.

What are regex flags?

Flags like i (case-insensitive), g (global), m (multiline), and s (dotall) modify how your regex matches text.

Regex Tester & Validator

This tool allows you to test and validate regular expressions in real-time. Enter your regex pattern and a test string to see if they match. You can also toggle flags like case-insensitive, global, and multiline to customize the behavior of your regex.

Regular ExpressionTest String

i - case-insensitivem - multilineg - globals - dot matches all

Why Use a Regex Tester?

Instantly debug and validate complex regex patterns.
Save time by testing your expressions before using them in code.
Understand flag behavior like i, g, m, and s.
Free and privacy-friendly — no data is sent to any server.

Common Use Cases

Regular expressions are powerful for pattern matching — used in validation, parsing, search-and-replace, and data cleaning. Whether you’re a frontend or backend developer, this regex tester makes it easier to experiment and learn.

Learn Regex Quickly

Not sure where to start? Try patterns like ^[a-z]+$ for lowercase validation or\d3-\d2-\d4 for numeric formats. Experiment freely and learn by doing!