About this Tool
Test and debug your Regular Expressions against custom text strings.
1Why Test Regex Locally?
Regular expressions (RegEx) are powerful patterns used for matching and manipulating text. However, they are notoriously difficult to debug and can lead to performance issues or security vulnerabilities (ReDoS) if not constructed correctly. Testing them online often requires you to paste proprietary code or private search queries, which can expose sensitive logic or data. This tool runs the RegEx engine natively in your browser, ensuring your patterns and test strings never leave your machine.
2Example: Common Patterns and Use Cases
Extract Emails: `/[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/g` Match Phone Numbers: `/\+?\d{1,4}?[-.\s]?\(?\d{1,3}?\)?[-.\s]?\d{1,4}[-.\s]?\d{1,4}[-.\s]?\d{1,9}/g` Find Duplicate Words: `/\b(\w+)\s+\1\b/gi`
3Interactive Highlighting and Capture Groups
Our tester provides real-time highlighting of matches and capture groups as you type. You can toggle flags like Global (g), Case-insensitive (i), and Multiline (m) to see exactly how they affect your search results. It also provides a detailed breakdown of each match, including starting indices, lengths, and named capture group values, making it easy to see exactly what your regex is capturing.
4Performance and Security Testing
Testing your regex against large datasets? Our tool uses a local execution engine that helps you identify slow patterns before they reach your production environment. By testing locally, you also ensure that you're not leaking sensitive test data to third-party logging servers while debugging complex validation logic.
5Privacy: Your Logic is 100% Private
Debugging complex validation logic for a new feature or an internal security tool? Secure Devutils executes your regular expressions locally. We don't track your search patterns, the regex logic you build, or the test data you provide. This ensures that your proprietary algorithms and sample data remain strictly in your control.
6RegEx in JavaScript (Quick Snippet)
```javascript const regex = /pattern/g; const str = "your text"; let match; while ((match = regex.exec(str)) !== null) { console.log(`Found ${match[0]} at index ${match.index}`); } ```
Privacy Guarantee
Secure Devutils operates exclusively in your browser using local web workers and JavaScript. Your source code, configurations, and sensitive text payloads are never transmitted across the network or stored on any external servers. It is completely safe for air-gapped environments.