🧪 Regex Tester offline
Free offline regex tester. Test and debug regular expressions with real-time matching and highlighting in your browser.
Regular Expression
Test String
Results
About Regex Tester
Regex Tester helps you test and debug regular expressions in real-time. Regular expressions (regex) are powerful patterns used for matching and manipulating text. This tool provides instant feedback with syntax highlighting and match details.
Features
- ✓Real-time regex testing with visual highlighting
- ✓Support for global, case-insensitive, and multiline flags
- ✓Display all matches with detailed information
- ✓Syntax error detection and reporting
- ✓Interactive flag controls
- ✓Works offline in your browser
How to Use
- 1.Enter your regular expression pattern
- 2.Select flags (g, i, m) as needed
- 3.Enter or paste test text
- 4.Click "Test Regex" to see matches highlighted
- 5.View match count and details below
How to Use
Enter your regex pattern, choose flags, paste a test string, and click Test Regex. Matches show up highlighted and listed below. I usually start with a small sample and expand once the pattern looks correct.
Example
Pattern: ^[A-Z]2\d4$ Text: AB1234 CD9999 invalid
- Type the regex pattern in the field.
- Toggle flags like
g,i, andm. - Paste the test string and run the matcher.
- Review highlighted matches and tweak the pattern.
Use Cases
Regex testing helps when you need:
- Validation patterns for email, IDs, or usernames.
- Extraction rules for URLs, phone numbers, or tags.
- Log parsing to pull structured data from text.
- Search-and-replace workflows in editors or scripts.
Tips & Best Practices
Start simple
Build a basic match first, then add groups, quantifiers, and anchors.
Test with real data
Synthetic strings hide edge cases. Use sanitized real examples when possible.
Watch for greedy matches
Use lazy quantifiers like .*? when you only want the smallest match.
Avoid catastrophic backtracking
Keep nested quantifiers minimal to avoid slow regex performance.
Comparison with online tools
Many regex sandboxes run on remote servers. TurboUtil runs locally, which keeps sensitive log lines and user data private.
Online testers
- Upload test strings to servers
- Potential logging or retention
- Require internet access
- Often include tracking scripts
TurboUtil
- All matching runs locally
- No uploads or tracking
- Works offline after load
- Instant feedback
FAQ
Why is my regex invalid?
The error message shows the syntax issue. Common mistakes include unescaped brackets or unclosed groups.
What flags are supported?
Global (g), case-insensitive (i), and multiline (m) are supported.
Is my data uploaded?
No. All testing happens in your browser.
Can I highlight multiple matches?
Yes. Use the global flag to find all matches.