Regular Expression Tester

Test and debug regular expressions against sample text in real-time. Free, secure, and works directly in your browser.

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Results

Matches: 0
Highlighted Text:

Debug Information

Quick Reference

Character Classes

  • . - Any character
  • \d - Digit [0-9]
  • \w - Word character [a-zA-Z0-9_]
  • \s - Whitespace
  • [abc] - Any of a, b, or c
  • [^abc] - Not a, b, or c

Quantifiers

  • * - 0 or more
  • + - 1 or more
  • ? - 0 or 1
  • {n} - Exactly n
  • {n,} - n or more
  • {n,m} - Between n and m

How to use Regular Expression Tester

  1. Enter your regular expression pattern in the input field.
  2. Paste or type your sample text into the provided text area.
  3. Click the 'Test' button to see matches and groups highlighted in real-time.
  4. Review the debug output and match results to refine your pattern.

Features

  • Supports complex regex syntax including lookaheads, groups, and quantifiers.
  • Provides real-time highlighting of matches and capture groups for instant feedback.
  • Includes a detailed debug panel showing step-by-step matching logic.
  • Works entirely in your browser with no data sent to servers for privacy.

Who Is This Tool For?

Ideal for developers, data analysts, and system administrators who need to write, validate, or troubleshoot pattern-matching logic for data extraction, validation, or search tasks.

Why Test Regular Expressions?

Regular expression testing is crucial for ensuring accurate pattern matching in data validation, text parsing, and search operations. A reliable regex tester helps developers debug complex patterns efficiently, reducing errors in applications that process strings, log files, or user input.

Frequently Asked Questions

Is this regular expression tester free to use?

Is my sample text or regex uploaded to a server?

How do I test my regular expression?

Does it support all regex syntax and flags?

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