Regex Tester – User Guide

The Regex Tester is an online utility designed to help you create, test, and debug regular expressions (regex) in real time. Whether you’re a beginner learning regex syntax or an experienced developer fine-tuning a pattern, this tool offers instant feedback and match highlighting to make regex easier to work with.

1. What is Regex?

Regex (short for regular expressions) is a powerful way to search, match, and manipulate text using patterns. It’s commonly used in programming, data validation, text processing, and web scraping.

Example:

Pattern: ^\d{3}-\d{2}-\d{4}$
Matches: 123-45-6789

2. Features of the Regex Tester Tool

• Real-time Testing: See matches instantly as you type your regex.

• Match Highlighting: Highlights all occurrences in the test string.

• Group & Capture Display: Shows numbered capture groups and their contents.

• Syntax Highlighting: Makes complex regex easier to read.

• Flags Support: Toggle case-insensitive, multiline, and global options.

• Error Detection: Shows syntax errors immediately.

3. How to Use the Regex Tester

1. Enter Your Regex Pattern – Type or paste your regular expression into the pattern field.

2. Add Test Data – Enter the text you want to test against.

3. Adjust Flags – Select options like i (ignore case), g (global), or m (multiline).

4. Review Matches – See highlighted matches and capture group results instantly.

4. Common Use Cases

• Validating email addresses or phone numbers.

• Extracting specific data from text or logs.

• Finding and replacing patterns in documents or code.

• Testing regex before using it in scripts or applications.