API services with PHP learning resources

Question

Hello

I want to learn API access systemically and I would like some recommendations for books/sites that cover the subject.

I have limited experience with the Google Checkout HTML system, so I'd like to understand the xml system for that. I'll need examples to be written in php/xml.

Basically, I need to get to know the nuts and bolts of popular API services so I can apply the knowledge to other services. I've got as far as I can unassisted, but I'm having a hard time understanding the basics due to the complexity of the system. I've managed to send xml to some services successfully, but I can't understand the process of receiving and processing the response. For example, the Google Checkout is meant to send information back when customers hit the return to site button, but I seem unable to receive it.

I am fairly familiar with Ajax, which seems similar in principle - if that helps.

If sample projects etc could be based on non payment services that would help.

Answer 1

For start the Twitter API is easy to use and with lot of tutorials available. Then you can go with Facebook, YouTube, Google Maps...

Answer 2

You can play around with public web service which almost don't require registration

http://www.service-repository.com/