Regex Tester
Test and debug regular expressions with real-time match highlighting.
2 matches
- utilitydock@zohomail.in
- support@example.org
What is the Regex Tester Tool?
Our free online Regex Tester helps you test, debug, and validate regular expressions against text datasets live in your browser. It displays matches instantly to speed up code development.
How to Use Regex Tester
- 1Enter your regex pattern and flags (e.g. g, i, m) in the top boxes.
- 2Paste your test text in the large dataset box.
- 3Inspect the live matching list and counts displayed in the results area.
Common Use Cases
- •Testing email, phone number, or date string validation formats.
- •Debugging regex match groups before embedding them in backend code.
- •Extracting specific text blocks from log files using regex patterns.
🔒 Privacy & Processing Notice
This tool processes all data entirely in your browser using client-side JavaScript. Your input is never uploaded to any server, ensuring 100% privacy and confidentiality. No data is stored, logged, or transmitted.
Frequently Asked Questions
What is a regular expression?
A regular expression (regex) is a sequence of characters that forms a search pattern, commonly used for string matching and search-and-replace actions.
What do the flags 'g' and 'i' mean?
The 'g' (global) flag searches for all matches in the text rather than stopping after the first. The 'i' (ignore case) flag makes search matching case-insensitive.
What is regex backtracking?
Backtracking occurs when a regex engine checks multiple pathways to find a match. Poorly written patterns can trigger excessive backtracking, blocking CPU processes.
Is Regex Tester free to use?
Yes, Regex Tester is 100% free with no signup required.
Is my data safe?
All processing happens in your browser. Your data never leaves your device.
Does it work offline?
Once the page loads, Regex Tester works entirely client-side.