Regex Tester
Test regular expressions against custom text in real-time with support for flags like global, case-insensitive, multiline, etc.
Result
Please check your inputs.
How to Use This Tool
Enter your regular expression pattern in the 'Regex' input field.
Type or paste the text you want to test in the 'Test String' area.
Select optional flags such as 'g' (global), 'i' (case-insensitive), or 'm' (multiline) to control matching behavior.
View real-time highlighted matches in the test string and a detailed match summary below.
Copy the matched results or the finalized pattern for use in your code.
What Is Regex Tester?
A Regex Tester is an interactive tool that lets you experiment with regular expressions (regex) against custom text and see matches instantly. Regex is a powerful pattern-matching language used in programming and text processing to search, validate, extract, or replace strings. It matters because it saves hours of manual searching and enables complex text operations—from validating email addresses to parsing logs. This tool eliminates guesswork by giving you immediate visual feedback, helping you debug patterns faster and learn regex more intuitively.
Formula
The tool applies the pattern to the text using the standard regex engine (e.g., JavaScript's RegExp). The core logic is: `text.match(new RegExp(pattern, flags))`. The 'pattern' is your regex (e.g., `\d+` for digits), 'flags' modify behavior (like 'g' for global, 'i' for case-insensitive), and the result is an array of all matching substrings (or details). The tool highlights each match in real-time, showing exactly what the pattern captures.
Tips for Best Results
🔍 Start small: Test simple patterns like `/hello/` before adding quantifiers or groups.
🚩 Use flags intentionally: 'g' finds all matches, 'i' ignores case, 'm' lets `^` and `$` match line boundaries.
✂️ Escape special characters: To match a literal dot, use `\.`; for a literal asterisk, use `\*`.
💡 Copy from examples: Grab proven patterns for emails, URLs, or dates and tweak them to fit your data.
Frequently Asked Questions
What is a regular expression (regex)?
A regular expression is a sequence of characters that defines a search pattern. It's used to find, validate, or manipulate text strings, such as checking if an email is formatted correctly or extracting phone numbers from a document.
How do I test a regex pattern with this tool?
Simply type your regex pattern into the dedicated field, enter your test text in the main area, and select any flags you need. The tool instantly highlights all matches, and a summary shows the number of matches and each matched substring.
What do regex flags like 'g' and 'i' mean?
'g' (global) makes the pattern find every match in the text instead of stopping after the first. 'i' (case-insensitive) ignores uppercase/lowercase differences. 'm' (multiline) changes how `^` and `$` work, making them match the start and end of each line rather than the whole string.