Free, fast, open-source developer tools that run entirely in your browser.
No tracking. No data collection. No sign-up. 100% client-side -- your data never leaves your browser.
| Tool | Description | Link |
|---|---|---|
| chmod Calculator | Interactive Unix file permission calculator with octal/symbolic output, common presets (755, 644), security warnings, and umask calculation | Open |
| TOML / JSON / YAML Converter | Convert between TOML, JSON, and YAML formats instantly. Auto-detect input, bidirectional conversion, syntax validation | Open |
| .env File Editor | Parse, edit, and convert .env files. Framework templates for Next.js, Django, Laravel, Express, Rails. Export to JSON, YAML, Docker env | Open |
| Cron Expression Generator | Build and decode cron expressions with a visual editor. Human-readable descriptions and next execution preview | Open |
| Docker Compose Validator | Validate docker-compose.yml with schema-aware checks. Detects invalid keys, circular dependencies, port issues | Open |
- Astro -- Static site generation with island architecture
- React 19 -- Interactive tool components
- Tailwind CSS v4 -- Utility-first styling
- Cloudflare Workers -- Edge deployment, globally distributed
# Install dependencies
npm install
# Start dev server
npm run dev
# Build for production
npm run build
# Preview production build
npm run preview- Privacy-first: Everything runs in your browser. Zero server calls, zero data stored.
- Fast: Static HTML + progressive hydration. No loading spinners.
- Free & open source: No paywalls, no premium tiers, no ads-before-content.
- Offline-capable: Works after first load, even without internet.
MIT