Regex Tester & Explainer
CoreTest regular expressions with real-time match highlighting, capture groups, and token explanation.
| # | Match | Index | Captured Groups |
|---|---|---|---|
| 1 | alex@example.com | 63 | None |
| 2 | support@devtools.local | 83 | None |
About Regex Tester & Explainer
A regular expression (regex) is a sequence of characters that forms a search pattern used for string matching, validation, and replacements. The Regex Tester allows developers to experiment with patterns, test against sample texts, and view captured groups immediately.
Zero-Upload Privacy Guarantee
Log files, customer emails, and data samples containing personally identifiable information (PII) should never be sent over the internet to test a regex. Testing locally guarantees total data privacy.
Key Capabilities & Features
How to use this regex tester online
Enter Regular Expression
Type your pattern in the regex field, such as `([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,})`.
Toggle Flags
Click flag toggles: 'g' (global), 'i' (case-insensitive), 'm' (multiline), 's' (dotAll), 'u' (unicode).
Provide Test String
Paste the text you want to evaluate. Matches highlight instantly.
Inspect Groups & Explanation
Review extracted capture groups ($1, $2) and the tokenized explanation breakdown.
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