Regex Tester
Test regular expressions in real-time with flag toggles, match highlighting, and capture group display.
The Regex Tester provides a real-time environment for writing and debugging regular expressions directly in the browser. As you type your pattern and test string, matches are highlighted instantly — no need to press a button or wait for a response.
Flag toggles
The tool supports all standard JavaScript regex flags — global (g), case-insensitive (i), multiline (m), dotAll (s), unicode (u), and sticky (y) — via toggle buttons. You can experiment with different flag combinations without editing the pattern string. This is much faster than manually typing /pattern/gim and adjusting.
Capture groups
Capture groups are extracted and displayed in a clear table format showing the group index and matched content. This is critical when writing patterns for data extraction — you can immediately see whether your groups are capturing the right substrings without writing a test script.
Who this is for
Anyone writing form validators, log parsers, URL matchers, or text extraction scripts. Having match highlighting and capture group visibility in the same view eliminates the constant context-switching between code and documentation.
Highlights
- Real-time match highlighting as you type
- Toggle buttons for all JavaScript regex flags (g, i, m, s, u, y)
- Capture group extraction displayed in a structured table
- Match count and execution feedback
- Supports complex patterns including lookahead and lookbehind