Nelson Minar, Software Engineer at Google is talking about how his team designed and deployed the Google AdWords API. The API allows developers to integrate with the platform in order to manage bids, optmize ROI/campaigns and keywords, customize UI and integrate advertising with backend systems. Nelson was also responsible for developing the Google Search API a couple of years ago.

The technology used was SOAP, WSDL and SSL with multiple authentication mechanisms. In order to make it simple to use there's no XML or HTTP work involved, this abstraction is possible via WSDL. The idea is to make the data model as the center of the design, the API shouldn't be thought as function calls.

In reality interop is hard to achieve, WSDL and SOAP doc/lit support is not unique and varies by toolkit: .NET, Java (Axis) toolkits are good; C++ (gSoap), Perl (SOAP::Lite) are OK, Python (SOAPpy, ZSI) and PHP not as easy. He then shows 3 different ways of sending no data and how the different toolkits handle them. Still doc/lit seems to Google as the only real choice.

Things that went right, according to Nelson:

• The switch to document/literal

• Stateless design

• The developer reference guide

• Developer tokens

• Thorough interop testing

• Private beta period

• Excellent tech support group

• Bulk methods

Things that went wrong:

• The switch to document/literal

• Lack of common data model

• Dates and time zones

• No gzip encoding wroking right now

• Quota confusion and anxiety

• No developer sandbox

• SSL (hard to debug, slow)