Regex Tester & Debugger | Real-time Matching, Flags & Groups
Test and debug JavaScript regular expressions in real-time. Features instant match highlighting, capture group visualization, and full support for ES6+ flags (g, i, m, s, u, y). 100% private and browser-based.
How to Use This Tool
- 1
Enter your regular expression pattern in the input field.
- 2
Toggle flags (g, i, m, s, u, y) to adjust matching behavior.
- 3
Type or paste your test string into the text area.
- 4
View matches, indices, and capture groups instantly in the results panel.
- 5
Hover over matches to see detailed information.
Use Cases & Examples
Form Validation Patterns
Validate complex user inputs like email addresses, passwords, phone numbers, or dates before implementing validation logic.
Data Extraction & Scraping
Test patterns for scraping or extracting specific data points (URLs, prices, IDs) from unstructured text.
String Manipulation & Replacement
Debug string replacement logic by verifying exactly what your regex matches before running `string.replace()`.
Learning & Experimentation
Learn and experiment with regex syntax, flags, and edge cases in a safe, instant-feedback environment.
About JavaScript Regular Expressions
Regular Expressions (Regex) are patterns used to match character combinations in strings.
This tool utilizes the ECMAScript RegExp standard, supporting modern features like lookaheads, lookbehinds, and named capture groups.
The 'Global' (g) flag finds all matches; without it, only the first match is returned. 'Multiline' (m) affects how ^ and $ anchors work.
Frequently Asked Questions
Q.Which regex engine does this tool use?
A. It uses the native JavaScript RegExp engine built into your browser. This ensures the results match exactly what you will see in your JavaScript applications.
Q.Is my data secure?
A. Yes. All processing happens locally in your browser's memory. Your regex patterns and test strings are never sent to any server.
Q.What regex flags are supported?
A. We support all standard JavaScript flags: Global (g), Ignore Case (i), Multiline (m), Dot All (s), Unicode (u), and Sticky (y).
Q.Does it support capture groups?
A. Yes, the tool highlights matches and lists all capture groups (numbered and named) with their indices.
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