Free Regex Tester - Test Regular Expressions Online | ToolZen
Test regular expressions in real-time. See all matches highlighted with position and captured groups.
Frequently Asked Questions
1. What regex syntax is supported?
Our regex tester uses JavaScript's regular expression syntax. It supports standard regex patterns including character classes (\d, \w, \s), quantifiers (+, *, ?, {n}, {n,m}), anchors (^, $), groups ((), (?:)), and alternation (|).
2. What flags are supported?
g (global): Find all matches, not just the first one. i (case-insensitive): Match regardless of case. m (multiline): ^ and $ match start/end of each line. s (dotall): Dot (.) matches newlines too.
3. Does it show match details?
Yes! Each match shows the matched text, its position in the string, and any captured groups. For global matches, all occurrences are displayed with their respective positions.
4. Common regex patterns
Email: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
Phone (US): \(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}
URL: https?:\/\/[^\s]+
Date (YYYY-MM-DD): \d{4}-\d{2}-\d{2}
Key Features
- Test Regex — Test regular expressions against any text
- Flag Support — Supports g, i, m, s, u flags
- Match Highlight — Matches highlighted in real-time
- Replace Mode — Test regex replace operations
- Real-Time — Results update as you type
How to Use
Step 1: Enter pattern
Type your regular expression pattern.
Step 2: Enter test text
Paste the text you want to search through.
Step 3: View matches
Matches are highlighted in real-time as you type.
Use Cases
Data Validation
Validate email addresses, phone numbers, and other formatted data.
Text Extraction
Extract specific patterns from large text documents.
Log Analysis
Search through log files for error patterns and anomalies.
Why Choose ToolZen?
| Feature | ToolZen | Other Tools |
|---|---|---|
| Privacy | 100% Client-Side | Data to Server |
| Cost | Completely Free | Freemium |
| Registration | No Signup | Account Needed |
| Features | Test + Replace + Flags | Test Only |