I got tired of using random online formatters that send my data to unknown servers. So I built a collection of 33+ developer tools that run entirely in your browser — no server, no data collection.
What's in there?
- JSON Formatter & Validator — with syntax highlighting and error detection
- CSV to JSON / JSON to CSV — bidirectional converter
- WeChat Markdown Editor — specifically formatted for WeChat articles
- Base64 Encoder/Decoder — for quick encoding tasks
- URL Encoder/Decoder — percent-encoding made easy
- Color Picker & Converter — HEX, RGB, HSL all in one
- Regex Tester — test patterns with live matching
- JWT Decoder — inspect tokens without sending them anywhere
- Timestamp Converter — Unix ↔ human-readable
- ... and 23+ more tools
Why client-side?
The key principle: your data never leaves your browser. Everything runs in JavaScript locally. No API calls, no analytics tracking your inputs, no "we might use your data for improvement."
For developers working with sensitive data (API keys, customer data, proprietary configs), this matters. You can format, convert, and validate without worrying about where your data goes.
Tech stack
Pure HTML + CSS + vanilla JavaScript. No frameworks, no build tools, no dependencies. Each tool is a standalone page that loads instantly.
The whole site is open source and hosted on a simple static server.
Try it out
🔗 tools.pixiaoli.cn
It's completely free, no sign-up required. Just open and use.
If you find it useful, I'd love to hear what tools you'd want added next. I'm actively building more based on what the developer community needs.
What free developer tools do you use daily? I'm always looking for ideas to add to the collection.
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