Learn Regex by Testing It Live

For beginner programmers, developers, and data scientists who need to learn, debug, and validate regular expressions interactively. Paste a pattern and sample text to instantly see what matches, which groups are captured, and where it fails — turning abstract syntax into concrete, learnable feedback.

Regex Pattern, Flags & Test String

Results update live as you type — no button needed. The Example button fills a sample input.

Matches, Groups & Explanation

Why use Regex Learning Tool?

Real-time match highlighting shows exactly what your pattern captures

Plain-English explanations of each capture group and match

Support for flags like global, ignore case, multiline, and dotall

Built-in common examples to learn from and modify

Debug failing patterns with clear feedback on where and why they break

FAQ

What regex flags can I use?

You can use common flags such as g (global), i (ignore case), m (multiline), s (dotall), and u (unicode). Separate multiple flags with no spaces, e.g., 'gi'.

How do I read the capture groups?

Each match is broken down into numbered groups. The output shows the full match and then each group's captured text, along with a plain-English explanation of what that group represents.

Why does my regex not match anything?

Check for common issues like missing escapes, incorrect quantifiers, or flags that change behavior. The tool provides feedback on where the pattern fails, helping you debug step by step.

Is this tool suitable for beginners?

Absolutely. It is designed for learners. The interactive feedback and explanations make it easy to understand how regex works without prior experience.

Example input

Try it with this sample — paste it into the box above:

pattern: \b(\w+)@(\w+\.\w+)\b
flags: g
test_string: Contact alice@example.com or bob@test.org for details.

How to use Regex Learning Tool

Enter or paste your data into the Regex Pattern, Flags & Test String box above.
The result appears instantly in the Matches, Groups & Explanation box — everything runs in your browser, nothing is uploaded.
Use Copy or Download to keep the result, or Example to load a sample first.