Swagger is an incredibly helpful tool that can be used to learn the ins and outs of an api. The whole thing is an opensource project (swagger.io) that is easy to install. All an api provider needs to do is write a json object specifying what the heck the api does. The json object encapsulates what end points the api has, what inputs it accepts, what outputs it produces and in what format(s), what errors could be returned etc. Once installed anyone can use the "Try it out!" button to send in requests. It's great fun to see exactly what is returned, whether it's an error or data. You can read all the documentation an api provider supplies but there is no substitute for playing around and actually interacting with the api without having to write your own client. Swagger proverbially is the stick that lets you poke the api to see what it does.

I reversed engineered the json object for the patentsview api and tried to get the patentsview people to steal it. It's here on my site instead of theirs. Feel free to use the "Try it out!" button after clicking on one of the get_endpoints. You can cut and paste the parameters shown on my sample pages or invent your own queries to see for yourself just how fun and useful the experience can be.

As far as I can tell the patentsview post end points do not work as evidenced in swagger. I've sent in email about it with a suggested correction but it's still broken for most modern browsers.

Pair Bulk is a similar patent api. They provide a swagger page for their api for the whole world to use.