Software Development

regex101

A tool for testing, debugging and visualizing regular expressions.

Overview

regex101 helps you test, debug and visualize regular expressions. Live matches, railroad diagrams, explanations and AI assistance help you inspect how a pattern behaves across supported regex flavors.

Updated Nov 15, 2026

2 features

Key Features

Regex explanations
Understand your regular expression with explanations of its tokens, groups, and flags. Regex conversion adapts patterns, flags, and replacements across flavors and explains compatibility changes.
Regex testing
See what matched and what each group captured, including named groups and values reusable in replacements or backreferences.

Pros and cons

Pros

It shows live matches and railroad diagrams for regular expressions.

You?

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Featured Video

See regex101 at work before you try it.

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2 questions

FAQs

What does regex101 do?

It tests, debugs and visualizes regular expressions with live matches, railroad diagrams, explanations and AI assistance.

Does regex101 support different regex flavors?

Yes. It supports multiple regex flavors, letting you test patterns across different regular expression implementations.

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Community reviews

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Tried this tool? Share your experience.

Write a review

2 features

Key Features

Regex explanations
Understand your regular expression with explanations of its tokens, groups, and flags. Regex conversion adapts patterns, flags, and replacements across flavors and explains compatibility changes.
Regex testing
See what matched and what each group captured, including named groups and values reusable in replacements or backreferences.

Pros and cons

Pros

It shows live matches and railroad diagrams for regular expressions.

You?

Be the first to rate regex101

Your review helps others make better decisions. No account needed. Takes about 10 seconds.

Featured Video

See regex101 at work before you try it.

Watch on YouTube

2 questions

FAQs

What does regex101 do?

It tests, debugs and visualizes regular expressions with live matches, railroad diagrams, explanations and AI assistance.

Does regex101 support different regex flavors?

Yes. It supports multiple regex flavors, letting you test patterns across different regular expression implementations.

regex101

Overview

Key Features

Regex explanations

Regex testing

Pros and cons

Pros

Be the first to rate regex101

Featured Video

FAQs

What does regex101 do?

Does regex101 support different regex flavors?

Community reviews

Community reviews

Key Features

Regex explanations

Regex testing

Pros and cons

Pros

Be the first to rate regex101

Featured Video

FAQs

What does regex101 do?

Does regex101 support different regex flavors?

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