Introducing Guzzle as the best HTTP client on PHP at this moment. Comparing with alternative libraries and different "hand-made" approaches.

Guzzle in Drupal 8 and Drupal 7 with usage example: migrating Twitter+OAuth modules to simple Guzzle implementation.

Guzzle code structure overview, Guzzle plugin system overview and examples, Guzzle service descriptions - way to create almost any service client via single JSON file.

Thought about global Guzzle service descriptions repository, because drupal modules are useful, but lets share it with other PHP world :)