About DevToolkit Pro100% Client-Side
100% Client-Side
Your Data Never Leaves Your Browser
All computation runs in your browser. 137 tools, your input never uploaded, 100% local. Fast, private, and works offline — no account required.
100% Client-Side
Every tool runs in your browser. No backend server, no API calls. Your data never leaves your device.
Privacy First
Your tool input is never tracked or uploaded. Your data stays on your device.
Works Offline
Add to your home screen and use it without an internet connection (PWA support).
Unicode Safe
Full support for multi-byte characters, including Chinese, emoji, and other non-ASCII text.
130+ Tools, 6 Categories
Data
JSON suite, CSV/YAML/XML conversion, Markdown preview
Text
String ops, text analysis, Base64/URL/HTML encoding
Code
Prettier formatting, JSON to TS/Go/Java, config generation
Security
Hash, AES/RSA encryption, JWT, Bcrypt, password tools
Network
API tester, HTTP cheatsheet, URL parser, CIDR, regex
Media
Image compression, QR code, color tools, timestamp, UUID
Built With
Next.js 14React 18TypeScriptTailwind CSSMonaco EditorWeb Crypto APIPrettierjs-yamlajv
About the Operator
- About the Operator
- Operator: Shuai Li (independent developer)
- Location
- Based in: Beijing, China
- Est.
- Established: 2025
- Mission
- This site is operated by an independent developer as a personal project. Our mission is to provide developers worldwide with a fast, private, always-free online developer toolkit. No paid plans, no data collection, no tracking.
Open Source Philosophy
We believe in transparency. Our tools use well-established, audited open-source libraries for core logic. The service is free and will remain so.