Regex Tester
Test regular expressions with live matching
What is a Regex Tester?
Test regular expressions against sample text. Regex patterns are used for text matching, validation, and extraction.
How to Use This Tool
- Enter your input — Provide the value required by Regex Tester (e.g., IP, domain, text) in the input field above.
- Configure options — Adjust any settings such as CIDR, key length, or format if the tool provides them.
- Click Calculate/Generate — Results appear instantly in the results panel below.
- Copy or export — Use Copy All or Download (CSV/PDF) to save results. All processing stays in your browser.
Understanding the Results
Output format: Test regular expressions with live matching. Results are shown with clear labels and can be copied for documentation, ticketing, or IPAM systems.
Accuracy: Calculations follow current RFCs and browser-native crypto where applicable. For DNS/WHOIS lookups, results reflect live network responses at query time.
Tips & Best Practices
• Keep inputs in correct format (e.g., valid IPv4 like 192.168.1.1, valid domain like example.com) to avoid validation errors.
• Bookmark this tool and try related tools: Developer Tools utilities are linked below as Related Tools.
• All NETCUE tools run client-side — no data leaves your browser. For sensitive data, you can use them offline after first load.
Frequently Asked Questions
Common flags: g (global - find all), i (case-insensitive), m (multiline), s (dot matches newline).
Yes — every NETCUE tool, including Regex Tester, is free, requires no login, and runs entirely in your browser. No input is sent to any server.
No. Regex Tester processes everything locally via JavaScript. Closing the tab clears the in-memory input. We do not log, store or transmit your data.
Test regular expressions with live matching — built for network engineers and developers, with instant results, copy/export, and related developer tools tools one click away.
Yes. After the page loads once, it works offline (service worker cache) and is fully responsive on mobile. Inputs stay 16px to avoid iOS zoom.