Regex Tester & Debugger
Test regular expressions in real-time with regex match highlighting, capture groups, and flag toggles.
About Regex Tester & Debugger
Build, test, and debug regular expressions (RegEx) with instant color-coded visual match highlights. Toggle global (g), case-insensitive (i), and multiline (m) flags, and inspect capture group breakdown.
How to Use Regex Tester & Debugger
Type your regular expression pattern and flags (e.g. `[a-z0-9]+` with `/gi`).
Enter or paste test string content in the test area.
View matched substrings highlighted in real time.
Inspect match count and capture group details.
Supported Formats & Limits
- Supported Inputs: TEXT
- Guest Maximum Size: 25 MB
- Logged-in Max Size: 100 MB
- System Compatibility: Windows, macOS, Linux, iOS & Android
Privacy & Security Guarantee
This tool processes your files entirely inside your web browser using client-side JavaScript, WebAssembly, and Canvas APIs. Your document is never uploaded to any external server, guaranteeing total confidentiality.
Frequently Asked Questions
What regex dialect is used?
Standard ECMAScript / JavaScript regular expression syntax with support for lookaheads, word boundaries, and character classes.