Google Checkout, our recently unveiled checkout option, has an API that exposes sophisticated functionality and programmatic interaction via XML over HTTP. Once you've created a sandbox account, the Checkout API's equivalent of "Hello World" is quite easy using cURL:

curl -d '<hello/>' https://<your-merchant-id>:\
<your-merchant-key>@sandbox.google.com/cws/v2/\
Merchant/<your-merchant-id>/request

When you're ready to start integrating with the Google Checkout API, read through the Developer's Guide, Sample Code and Developer's Cookbook (for implementation-focused articles), and connect with other API developers in the Developer's Forum.

The Google Desktop Team just announced a Google Desktop Gadget Contest! The Desktop blog has the details, but here are a few highlights:

• The contest runs through July 31 (winners will be announced August 21)
• Everyone who submits a published Gadget will get a limited edition Google Desktop Developer T-shirt (there are other Google-y prizes too)
• Top prizes: $5,000 for 1st place, $2,000 for 2nd place, and $1,000 for 3rd place
• Primary judging criteria: popularity, visual appeal, use of new features (such as transparency/animation, Google Talk API integration, personalization, etc.)

And be sure to check out the Google Desktop Gadget Designer, a new IDE and WYSIWYG UI creator for making Google Desktop Gadgets.

Google's Summer of Code mentors will be completing their mid-term evaluations of student progress this week. For those of you coming to the O'Reilly Open Source Convention, we will be sharing some of the aggregate data from these surveys, along with other program statistics at both Chris DiBona's session and at our GSoC BoF at OSCON 2006. If you'll be at the conference, feel free to stop by.

Jon Udell at InfoWorld has been tinkering with the first GData API (Google Calendar's), check out what he has to say:

"Along with HTTP Basic, Digest, and a couple of others, this Python HTTP library [httplib2] will now handle Google-style authentication. That's really the only tricky thing about using Google Calendar's API. Everything else is URLs and Atom entries. There are Java and C# wrappers for this stuff, but I'm having a ball just using Python's interactive mode to explore the Calendar API. Among the things I can easily do: search for entries matching dentist, search for entries after June 10, receive the results of any query as an Atom or RSS feed..."

"Most discussion of Gcal has (appropriately) focused on its user interface, which puts many a conventional fat client to shame in terms of both its responsiveness and its ease of use. From my perspective, though, what matters equally is an API that's powerful, flexible, and easy to use."