More in Why We're Decoupling Drupal blog post.
A caching web client for fetching and storing remote resources
Remote image fetching and local transformations, including resizing, cropping, and compositing
Development log and debugging tools
Outpost has native support for these libraries:
Stash. Configurable by environment. Use Memcache in production site, use a filesystem cache or no cache in development.
Guzzle. The Outpost web client wraps a Guzzle client, and caches most requests by default. Used to fetch remote assets.
Monolog. Configurable by environment. Verbose logging in development.
ImageMagick. Runs ImageMagick from the shell. Support for resizing, limited support for composing.
Libraries are available for integration with the following: