Regex Tester
Regular Expressions, or "Regex," are one of the most powerful yet intimidating tools in a developer's arsenal. At its core, Regex is a sequence of characters that forms a search pattern, allowing you to find, validate, and manipulate text with surgical precision. However, writing the perfect pattern often involves a frustrating cycle of trial and error. Our free Regex Tester is built to break that cycle by providing a live, interactive environment for writing and debugging your patterns.
# About This Tool
A Regex Tester is a specialized debugger for Regular Expressions. It functions by taking two inputs: a Regular Expression Pattern (the logic) and a Test String (the data). The tool then applies the pattern to the string using the browser's native JavaScript RegExp engine and visualizes the results.
Regular Expressions, or "Regex," are one of the most powerful yet intimidating tools in a developer's arsenal. At its core, Regex is a sequence of characters that forms a search pattern, allowing you to find, validate, and manipulate text with surgical precision. However, writing the perfect pattern often involves a frustrating cycle of trial and error. Our free Regex Tester is built to break that cycle by providing a live, interactive environment for writing and debugging your patterns.
# How Does Regex Tester Work?
- 1Input your Regular Expression pattern into the top field.
- 2Toggle flags like Global (g) or Case-Insensitive (i) as needed.
- 3Paste your test text into the center window.
- 4Observe real-time highlighting of matches and capture groups.
# Who Should Use This Tool?
Validating form inputs (emails, phone numbers, passwords).
Extracting specific data points from large log files or HTML.
Testing search-and-replace patterns for code refactoring.
Learning Regular Expression syntax through visual experimentation.
Privacy & Security
We prioritize your privacy. All processing for the Regex Tester occurs locally on your device. ProUtilityApp does not upload, store, or log your data, ensuring your sensitive information remains entirely under your control. Once you close the tool or perform a new task, all temporary assets are cleared from memory.
# Frequently Asked Questions
Which regex flavor is this?▼
How do I match a literal dot?▼
Does it support lookbehinds?▼
This tool is actively maintained to support modern standards and evolving browser security.
Last updated: March 2025 • Free privacy-first browser tools.