Congrats on posting about something you did on HN! Here's some feedback:

- Like a lot of such generators, you make the mistake of picking random x,y coordinates and not checking for collisions, which can result in situations like that (http://i.imgur.com/M7LyPqD.png)

- generating a nicer URL, as other commenters have pointed out, would be nice

- just as a FYI, when products use the terminology "as a service", it's typically because the product can be used in a programmatic way (i.e. it exposes its functionality through an API). That would be a good next step for your project!