Debug patterns without leaving Notion.
Regex Tester runs your pattern against any test text using the browser's native JavaScript RegExp engine. Matches are highlighted live as you type, a counter shows exactly how many were found, and invalid patterns are flagged immediately — no page reloads, no external services, and nothing ever leaves the widget.
⚙️ Settings & Customization
- Theme
- Language
- Size
- Transparent background
- 🎨 Accent Color
Changes apply live — the embed link and preview update instantly.
📖 How to embed in Notion
- Copy the embed link from the sidebar on the right.
- Open the Notion page you want the widget on and type
/embed. - Paste the link into the embed dialog and press
Embed link. - Drag the embed's bottom edge to resize it to taste.
🆕 What's new in v1.0
- ✦ Live match highlighting with match counter
- ✦ Full flag support (g, i, m, s, u, y)
- ✦ Instant invalid-pattern feedback
- ✦ 21 UI languages · fully offline
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