Common Patterns
\d- digit,\w- word char,\s- whitespace+- one or more,*- zero or more,?- zero or one^- start,$- end()- capture group,(?:)- non-capture group
🔍 What is Regex Tester?
Regular Expressions (Regex) are powerful tools for finding and manipulating patterns in text. This tester validates regex patterns in real-time with highlighted match visualization. Test capture groups, flag settings, and string replacement all in one place. Includes presets for common patterns like email, URL, and phone numbers to get started quickly.
📊 Common Regex Patterns
| Purpose | Pattern | Description |
|---|---|---|
| [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,} | Basic email format | |
| URL | https?://[^\s]+ | http/https URLs |
| Numbers | \d+ | One or more digits |
| Trim spaces | ^\s+|\s+$ | Leading/trailing whitespace |
💡 Regex Writing Tips
- g flag: Global search, find all matches
- i flag: Case-insensitive matching
- Capture groups (): Extract matched portions, reference with $1, $2
- Non-greedy *?: Match as few characters as possible
Frequently Asked Questions
How do I match special characters?▼
Escape them with \. Examples: \. (period), \? (question mark), \[ (bracket). Backslash itself needs \\ (double).
Capture vs non-capture groups?▼
Capture groups () store the match for backreference ($1, $2). Non-capture groups (?:) only group without storing.
Why is my pattern not working?▼
Check your flags. Without g, only the first match is found. Also, JavaScript regex may differ slightly from other languages.
What is Regex Tester?
Test regular expressions against sample text with instant highlighting of matches. See capture groups, test different flags (g, i, m), and debug your patterns visually.