Introduction
Regular expressions (regex) are powerful pattern-matching tools for text processing, but they can be notoriously difficult to write and debug. Our Regex Tester provides an interactive environment to test, validate, and optimize your regular expressions against real text in real-time.
Whether you're validating email addresses, extracting data from log files, parsing complex text formats, or building search-and-replace patterns, this tool helps you get your regex right before deploying it to production. See matches highlighted instantly, view detailed match information including position ranges and capture groups, and identify errors before they cause problems.
The tester runs entirely in your browser with no server-side processing. Your test data and patterns are private and never transmitted. Support for JavaScript, Python, PHP, and Java regex syntax ensures patterns work across different programming environments. With 75+ built-in templates organized into 10 categories, you can quickly find and customize patterns for common use cases.
Key Features
- 1 Real-time regex testing with instant match highlighting
- 2 Multi-language support: JavaScript, Python, PHP, and Java syntax
- 3 75+ built-in regex templates across 10 categories (validation, extraction, browser UA, HTML, etc.)
- 4 Support for /pattern/flags syntax input format
- 5 Comprehensive flag support: global (g), case-insensitive (i), multiline (m), dotall (s), unicode (u), sticky (y)
- 6 Detailed match information: position ranges, length, and capture groups ($1, $2, etc.)
- 7 Interactive modal for template details with multi-language code examples
- 8 Syntax highlighting and error detection with helpful messages
- 9 Quick search and category filtering for templates
- 10 Test text editor with replace functionality
- 11 Copy regex code in multiple programming languages with one click
- 12 Privacy-focused: all processing happens locally in your browser
How to Use
- 1 Enter your regular expression pattern (supports both plain pattern and /pattern/flags format)
- 2 Select the appropriate flags (g, i, m, s, u, y) for your use case
- 3 Type or paste your test text in the text area below
- 4 Watch matches highlight in real-time with detailed position and group information
- 5 Browse 75+ templates organized by category (validation, extraction, browser UA, HTML, etc.)
- 6 Click on any template to view detailed descriptions and multi-language examples
- 7 Use the replace tab to test replacement patterns
- 8 Copy the final regex code in your preferred programming language (JavaScript, Python, PHP, Java)
Why Choose This Tool
Multi-Language Support
Test and export regex patterns for JavaScript, Python, PHP, and Java. View syntax differences and copy code in any language with one click.
75+ Template Library
Access a comprehensive collection of regex templates organized into 10 categories including validation, extraction, browser detection, HTML parsing, and more.
Enhanced Match Details
View comprehensive match information including position ranges, length, and capture groups. Perfect for debugging complex patterns.
Flexible Input Format
Enter patterns using either plain text or /pattern/flags syntax. The tool automatically detects and parses flags from your input.
Privacy First
All testing happens locally in your browser. Your regex patterns and test data are never sent to any server.
Beginner Friendly
Plain English descriptions and categorized templates make regex accessible to newcomers while power users get advanced debugging tools.
Common Use Cases
Validating user input: email addresses, phone numbers, zip codes, credit cards
Browser and device detection: Chrome, Firefox, Safari, mobile devices, operating systems
HTML parsing: extracting links, scripts, styles, meta tags, iframes, and other elements
Extracting data from logs: IP addresses, timestamps, request IDs, user agents
Text processing and transformation: find and replace operations with capture groups
Web scraping: matching URLs, HTML tags, CSS selectors, structured data
Data cleaning: removing special characters, formatting text, extracting specific patterns
API development: validating request parameters, parsing response formats, route matching