Regex Tester
Test and debug your Regular Expressions in real-time. Analyze matches, capture groups, and validate patterns instantly.
Enter your regex pattern without slashes /.../'
Flags
Enter the text you want to test against
MATCH PREVIEW & HIGHLIGHTS
No matches found for the current pattern.
Regex Cheat Sheet
Character Classes
. | Any character except newline |
\w | Word char (a-z, A-Z, 0-9, _) |
\d | Digit (0-9) |
\s | Whitespace (space, tab, newline) |
[abc] | Match a, b, or c |
[^abc] | Not a, b, or c |
Quantifiers
* | 0 or more |
+ | 1 or more |
? | 0 or 1 |
{3} | Exactly 3 |
{3,} | 3 or more |
Mastering Regular Expressions for Data Validation
Regular expressions, commonly known as Regex, are powerful tools used by developers and data analysts to search, match, and manipulate text strings based on specific patterns. Whether you are validating email addresses, extracting dates from logs, or cleaning up messy data, regex is an indispensable skill in modern programming.
Why Use a Regex Tester?
Writing complex regex patterns can be challenging. A single misplaced character can break your entire validation logic. This Real-time Regex Tester provides an instant feedback loop, allowing you to:
- Visualize Matches: See exactly which parts of your test string are being matched by your pattern with highlighted results.
- Debug Flags: Experiment with different flags like
global (g)andcase-insensitive (i)to see how they affect your search scope. - Learn Syntax: Use the integrated cheat sheet to quickly reference common character classes and quantifiers without leaving the tool.
Common Regex Use Cases
Email Validation
^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$Matches standard email formats like [email protected].
Date Format (YYYY-MM-DD)
^\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12]\d|3[01])$Validates ISO 8601 date strings.
Strong Password
^(?=.*[A-Za-z])(?=.*\d)[A-Za-z\d]{8,}$Enforces min 8 chars with at least one letter and one number.
Hex Color Code
^#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3})$Matches valid hex color strings like #fff or #000000.
Note: The Javascript regex engine is used for all validations on this page. Some advanced features available in PCRE or Python regex implementations may not be supported.