Why Use This Regex Tester?
Regex is powerful but notoriously hard to debug. A single misplaced quantifier or unescaped character can silently match wrong patterns or crash your application. This tester gives you instant visual feedback — see exactly which characters match, which capture groups fire, and where your pattern fails.
Common Use Cases
- Form validation: Test email, phone, URL, and password patterns before adding them to your frontend or backend validation.
- Log parsing: Extract timestamps, IP addresses, error codes, and user IDs from server logs.
- Data extraction: Pull structured data from unstructured text — prices, dates, identifiers, or custom formats.
- Find and replace: Test complex substitutions with capture groups before running sed, grep, or IDE find-replace.
- Code refactoring: Test patterns for renaming variables, updating imports, or migrating APIs across your codebase.
Regex Quick Reference
| Pattern | Matches |
|---|---|
| \d | Any digit (0-9) |
| \w | Word character (a-z, A-Z, 0-9, _) |
| \s | Whitespace (space, tab, newline) |
| . | Any character except newline |
| + | One or more of the preceding token |
| * | Zero or more |
| ? | Zero or one (optional) |
| (abc) | Capture group |
| [a-z] | Character class (range) |
| ^ $ | Start / end of line |