Free, Private & Browser-Based Regex Tester
Build, test, and debug regular expressions with real-time match highlighting — entirely in your browser.
Regex Shuttle is a privacy-first regular expression testing tool. Patterns and test strings are evaluated entirely in your browser using the native JavaScript RegExp engine — nothing is uploaded to any server, making it safe for testing patterns against sensitive data like logs, emails, or source code.
- Real-Time Matching: Matches highlight as you type, with capture groups broken out per match.
- JavaScript RegExp Engine: Test exactly what your JS/TS code will run — flags
g,i,m,s,usupported in the UI. - Pattern Explainer: Plain-language breakdown of what each part of your pattern does.
- Common Pattern Library: Ready-made patterns for emails, URLs, dates, IP addresses, and more.
- 100% Private: All evaluation happens client-side. No pattern or test data ever leaves your device.
- Bilingual UI: Native English and Chinese interfaces with full SEO localization.
- Framework: Next.js 16 (App Router, static export) + React 19
- Language: TypeScript 5
- Styling: Tailwind CSS 4 + shadcn/ui primitives
- i18n: next-intl with URL-based routing
- Theming: System / Light / Dark three-state theme
- Deployment: Cloudflare Workers static assets (
output: "export")
- Node.js 18.17 or later
git clone https://github.com/ShuttleLab/regex-shuttle.git
cd regex-shuttle
npm install
npm run devOpen http://localhost:3000 to see the application running.
| Command | Description |
|---|---|
npm run dev |
Start the Next.js dev server |
npm run build |
Static-export build into out/ (incl. locale post-processing) |
npm run lint |
Run ESLint |
Regex Shuttle deploys as static assets on Cloudflare Workers. The build emits to out/, which wrangler.toml points at; scripts/postbuild.mjs promotes the default-locale pages to the web root and fixes the lang attribute on Chinese pages.
This project is licensed under the MIT License.