Regex Match Tester & Validator
Test JavaScript regular expression patterns against test strings with live match count.
Regex Match Tester & Validator
Test JavaScript regular expression patterns against test strings with live match count.
About Regex Match Tester & Validator
The Interactive Regular Expression (Regex) Tester & Debugger evaluates PCRE and JavaScript regular expressions against test strings in real time with syntax highlighting, capture group inspection, and replacement pattern testing.
How to Use Regex Match Tester & Validator
Step 1
Enter your regular expression pattern in the pattern bar.
Step 2
Select desired regex flags (`g`, `i`, `m`).
Step 3
Paste your sample test text into the test pane.
Step 4
Inspect the highlighted matches and capture group table.
Practical Use Cases for Regex Match Tester & Validator
Input Validation & Form Sanitization
Test email, phone number, password complexity, and postal code regex patterns before deploying to production web forms.
Log Parsing & Data Extraction
Extract IP addresses, timestamps, and error codes from server log streams using named regex capture groups.
Input & Output Examples
Matching Emails with Regex
Pattern: /([a-zA-Z0-9._%+-]+)@([a-zA-Z0-9.-]+\.[a-zA-Z]{2,})/g, String: "contact hello@renderxd.com"1 Match Found | Full Match: "hello@renderxd.com" | Group 1: "hello" | Group 2: "renderxd.com"
Key Features & Performance
- ✓Live real-time match highlighting in test string pane.
- ✓Inspects full matches, index positions, and capture groups (numbered and named).
- ✓Regex flags selector: Global (`g`), Case-Insensitive (`i`), Multiline (`m`), DotAll (`s`), Unicode (`u`).
- ✓Built-in library of common regex patterns: Email, URL, IPv4, IPv6, Phone, UUID, Dates.
- ✓100% Client-Side execution guarantees test data privacy.
Key Terminology & Definitions
Capture Groups `(...)`
Sub-patterns enclosed in parentheses that capture specific substrings from the overall match for extraction or replacement.
Catastrophic Backtracking
A performance pitfall where nested quantifiers cause exponential execution time on non-matching strings, causing CPU freeze.