I am currently working on a REST/JSON API that has to provide some services through remote websites. I do not know the end-customers of these websites and they would/should not have an account on the API server. The only accounts existent on the API server would be the accounts identifying the websites. Since this is all RESTful and therefore all communication would be between end-user browser (through javascript/JSON) and my REST API service, how can I make sure that the system won't be abused by 3rd parties interested in increasing the middleman's bill? (where the middleman is the owner of the website reselling my services). What authentication methods would you recommend that would work and would prevent users from just taking the js code from the website and call it 1000000 times just to bankrupt the website owner? I was thinking of using the HTTP_REFERER , and translate that to IP address (to find out which server is hosting the code, and authenticate based on this IP), but I presume the HTTP_REFERER can easily be spoofed. I'm not looking for my customer's end customers to register on the API server, this would defeat the purpose of this API.
Some ideas please?
Thanks, Dan