Regular Expression (Regex) Tester
Text & String Tools100% Client-SideTest and debug regular expressions in real-time with visual match highlighting and capture groups.
//gi
Templates:
Test String114 chars
Matches Found:2
SponsorNon-intrusive
What is Regular Expression (Regex) Tester?
A powerful real-time Regular Expression testing tool. Test regex patterns with instant match highlighting, detailed capture group inspection, support for common flags (g, i, m, s, u), and a cheat sheet of popular patterns.
How to Use Online
- 1Enter Regex PatternType your regular expression pattern into the pattern input (e.g., ^[a-zA-Z0-9_]+$).
- 2Set Regex FlagsToggle flags like Global (g), Case-Insensitive (i), and Multiline (m).
- 3Paste Test ContentEnter or paste sample text in the test box to see real-time color highlights.
- 4Inspect Match GroupsReview match count, capture group values, and start/end character indices.
Key Features
- Real-time syntax evaluation as you type
- Visual match highlighting with index positions
- Detailed breakdown of capture groups
- Toggle regex flags: Global (g), Case Insensitive (i), Multiline (m), DotAll (s), Unicode (u)
- Pre-built common templates (Email, Phone, URL, IPv4, Slug, Date)
Common Use Cases
- Validating form inputs (email, phone numbers, postal codes)
- Extracting specific substrings from server log files
- Building search and replace rules for text processing
Frequently Asked Questions
This tool uses the standard ECMAScript (JavaScript) RegExp engine built into your browser.