14 essential developer tools, all running locally in your browser. No server, no tracking, no sign-up.
- 100% Private — All processing happens in your browser. Zero data collection, zero cookies, zero analytics.
- Works Offline — Once loaded, all tools work without internet. PWA-ready.
- 7 Languages — English, Chinese, Japanese, Korean, Spanish, Portuguese, French.
- Always Free — No premium tiers, no usage limits, no sign-up.
| Tool | Description |
|---|---|
| JSON Formatter | Format, validate, and beautify JSON with precise error location |
| Base64 Encoder/Decoder | Encode and decode Base64 strings instantly |
| URL Encoder/Decoder | URL-encode and decode text |
| JSON ↔ CSV Converter | Convert between JSON and CSV formats |
| JWT Decoder | Decode and inspect JWT tokens |
| Timestamp Converter | Convert between Unix timestamps and human-readable dates |
| UUID Generator | Generate UUID v4 identifiers |
| Hash Generator | Generate MD5, SHA-1, SHA-256, SHA-512 hashes |
| Lorem Ipsum Generator | Generate placeholder text |
| Diff Checker | Compare two texts and find differences |
| Color Converter | Convert between HEX, RGB, HSL color formats |
| Markdown Preview | Live preview of Markdown content |
| CSS Gradient Generator | Create CSS gradients visually |
| Privacy Policy | Transparent privacy information |
- Vanilla HTML/CSS/JavaScript
- No frameworks, no build step
- Cloudflare Pages
Just open index.html in your browser. No server or build tools required.
# Clone and open
git clone git@github.com:dongze1213/devtools-site.git
cd devtools-site
open index.htmlMIT