Introduction

At heart, Google data APIs (GData) use Atom feeds and entries (XML) as a data format and HTTP as a protocol for data transmission -- extending the Atom Publishing Protocol. We publish a number of client libraries to make interacting with Google data APIs easier. However, you're always welcome to use lower-level tools to work with our services, and it's pretty easy to do with a little guidance.

cURL is a command-line application for performing requests using a variety of protocols including HTTP. cURL is often used by developers to test Google data services, as it allows supports the HTTP functionality required to interact with the APIs at a low level.

cURL only provides support for performing the HTTP communication, so knowledge of the GData protocol, the service-specific protocol and the XML data format used is a prerequisite for working with the application. Some other tools are mentioned in this article for making these tasks easier.

This article uses examples based upon the Picasa Web Albums data API. However, all these examples can be readily applied to other Google data APIs. 

For the rest of this article, visit the Developer Knowledge Base

Please add comments below using the 'Discuss this page' feature if you want to discuss this article with your fellow developers or share feedback with Google.