About SmartTools

SmartTools (利器网) is a small, independently run collection of free online tools for everyday money questions and developer chores. It is built and maintained by one developer who wanted simple, fast tools without sign-ups, pop-ups or uploading private data.

What you can do here

• Compound interest, SIP and CAGR calculators to plan savings and compare investments.
• An internet speed test that measures ping, jitter, download and upload speed.
• A JSON editor to validate, format, minify and explore JSON as a tree.
• A QR code generator with custom colours, shapes and logos.

How the tools are built

Wherever possible the tools run entirely in your browser, so what you type stays on your device. Each tool page includes a written guide that explains the concepts behind it, how to use it and answers to common questions, in both English and Chinese.

The site is free to use and is supported by advertising on content pages. Ads never appear on our legal, contact or error pages.

Feedback

We add and improve tools based on what users ask for. If you have an idea, find a bug or spot a mistake in a guide, please email admin@stutil.com.