JSON generator

In the past few months, I was working on a project where it was needed to consume some JSON objects from some web service that should be developed by another team. I wanted to test my part of the software separately, but I didn't manage to find a decent online tool that should provide JSON structure via REST. So I decided to build one on my own. After some time of refactoring and visual redesigning, it went live. You can find it on http://json-gen.com/ All thoughts and suggestions about it are welcome.