Regex Tester
Test and debug regular expressions against your text in real time.
match(es) found
How to use Regex Tester
- Enter your regex pattern between the slashes and set any flags (g, i, m).
- Paste your test string into the text area.
- See the matches and count update live as you edit.
- Refine the pattern until it matches exactly what you need, then copy it into your code.
What is Regex Tester?
A regular expression (regex) is a pattern that describes a set of strings — used to search, match, validate and replace text. A regex tester evaluates your pattern against sample input and shows the matches in real time.
Flags modify behavior: g finds all matches, i makes it case-insensitive, m enables multiline. Testing interactively helps you confirm a pattern does exactly what you intend before using it in production.
About the Regex Tester
The Regex Tester lets you write a regular expression, set flags, and immediately see what it matches in your sample text — match count and the matched values update as you type. It's the fastest way to build, debug and validate a pattern before dropping it into your code.
Regular expressions are powerful but easy to get wrong. Testing interactively — tweaking the pattern and watching matches change live — turns trial-and-error in your editor into instant feedback here. Great for validation rules, search-and-replace, data extraction and parsing.
It uses your browser's JavaScript regex engine, runs entirely on your device, and is free.
Frequently Asked Questions
Learn more
Regular Expressions for Beginners: A Practical Introduction
Regex looks like line noise but it is incredibly useful. Here is a beginner-friendly introduction to matching patterns, with examples you can use.
Read the guide