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Regex Online (Free & No Login)

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Regex Tester Online — Free Regular Expression Validator & Debugger

⚡ Regex Tester

Test, validate and debug regular expressions in real-time

✓ Free ✓ No Signup ✓ Real-time
Zero Data Stored
Instant Results
Mobile Friendly
Browser-Based
No Ads
Quick Patterns — Click to Load
Regular Expression
/ /
Test String
0 matches
Highlighted Output
Matches will be highlighted here…
🔍Enter a pattern and test string to see matches.
Result will appear here…
💡Enter a pattern to see its breakdown.

How to Use This Tool

  1. Type your regex pattern in the /pattern/ bar at the top. No need to add forward slashes.
  2. Toggle flags — g (global), i (case insensitive), m (multiline), s (dot all).
  3. Paste your test text in the Test String box — matches highlight instantly.
  4. Use the Replace tab to preview substitutions, or Explain to understand your pattern.

Common Regex Patterns

Email: ^[\w.-]+@[\w.-]+\.\w+$ Phone: \b\d{10}\b URL: https?:\/\/[\w\-\.]+\.\w+ Password: ^(?=.*[A-Z])(?=.*\d).{8,}$ Date: ^\d{4}-\d{2}-\d{2}$ Hex: ^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})$

Key Features

⚡ Real-time Matching Results update instantly as you type — no button needed.
🎯 Match Highlighting All matches are highlighted inline in the output panel.
🔄 Replace Preview Test replacements using $1, $& capture group syntax.
💡 Pattern Explainer Get a plain-English breakdown of what each part of your regex does.
📦 Quick Patterns One-click load for email, phone, URL, password and more.
🔗 Shareable Links Share your pattern and test string via a URL with one click.

Frequently Asked Questions

What is a regular expression (regex)?
A regular expression is a sequence of characters that defines a search pattern. It's used for string matching, validation, extraction, and replacement in almost every programming language including JavaScript, Python, PHP, and Java.
What do the regex flags mean?
g (global) finds all matches, not just the first. i makes matching case-insensitive. m makes ^ and $ match line starts and ends. s makes . also match newline characters.
How do I use capture groups in the Replace tab?
Use parentheses () in your pattern to create capture groups. In the replacement field, reference them as $1, $2 etc. For example: pattern (\w+)@(\w+) with replacement [$1 at $2].
Is my text data safe?
Completely. All regex processing runs locally inside your browser. No text, pattern, or data is sent to any server. Your input stays entirely on your device.
Is this tool free?
Yes — 100% free, no account required, no usage limits.