Choose the tool you need

What you can do here right now

• JSON to ERD turns a JSON document into a draggable entity relationship diagram, so an undocumented API response or config file becomes readable.
• API Tester sends HTTP requests straight from your browser and shows the full response, so you can check whether an endpoint behaves the way you expect.
• QR Code Generator turns a link, some text or contact details into a downloadable QR code for business cards, posters and event check-in.
• More tools get added over time, and every new one follows the same rules, so there is nothing new to learn.

How every tool here works

• Open the page and start working. There is no account to create and nothing to install.
• Whatever you type is processed inside your own browser, because this site has no backend that could receive it.
• You can verify that yourself. Open the network tab in devtools and look for a request carrying your data.
• Some tools remember your last input in browser local storage so you can pick up where you left off. Clearing it removes the data.
• The interface is available in English and Chinese, switchable from the top right of any page.
• Dark and light themes follow your system setting and can also be pinned manually.

When these tools are the right choice

• Your data should not leave the company network, so pasting it into a service that uploads is not an option.
• You need to do something once and do not want to install desktop software or sign up for it.
• You are working on someone else’s machine and a browser is all you have.
• You need to demonstrate or verify something during a meeting and it has to work immediately.

What this site deliberately does not do

• There are no accounts, so nothing syncs across devices and a different machine means starting over.
• No server does the work for you, so very large inputs are bounded by browser memory and performance.
• API Tester can only reach services that allow cross-origin requests. That is a browser security rule, and no proxy will be added to work around it.
• No analytics service is installed and no user profile is built.
• Any feature that genuinely needs a server does not get built. It is replaced with something achievable in the browser instead.

If the tool you want is not here yet

• Tell me what you need through the contact page.
• When reporting a bug, include what you did and what you expected. That finds the problem far faster than a report that something is broken.
• The about page explains why the site is designed this way.