Regex Tester
Test JavaScript regular expressions with live match highlighting, flags and capture groups.
Contact us at hello@toolsink.com or press@toolsink.com.
- #1 [14–32] “hello@toolsink.com”groups: $1=“hello”$2=“toolsink.com”
- #2 [36–54] “press@toolsink.com”groups: $1=“press”$2=“toolsink.com”
What is the Regex Tester?
The Regex Tester runs your regular expression against sample text as you type, highlighting matches and listing capture groups in real time. It uses the JavaScript (ECMAScript) regex engine, so patterns behave exactly as they will in browsers and Node.js.
Both the pattern and the sample text stay in your browser — nothing is uploaded.
How to use the Regex Tester
- 1Type your regular expression into the pattern box.
- 2Add flags (g for global, i for case-insensitive, m for multi-line, s for dotAll).
- 3Paste your target text into the sample area.
- 4Watch matches highlight as you type — capture groups appear underneath.
Key features
- Live match highlighting as you type
- Capture-group inspector
- All standard JavaScript flags (g, i, m, s, u, y)
- Handles multi-line sample text
Frequently asked questions
Which regex flavour does the tool use?
JavaScript's ECMAScript engine, so patterns transfer directly to browser and Node.js code.
How do I test a Python regex?
Most patterns are compatible, but Python-only syntax such as `(?P<name>...)` named groups differs — test those in Python.
Does the tool save my patterns?
Only in the current tab. Refreshing the page clears the state.
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