Hi Emarthinsen,
We use incoming/outgoing hooks that communicate with a very simple slack PHP service/class. For CapsuleCRM the command 'elvis leads' dispatches a call to the capsuleCRM API, parses the results and outputs does in the channel (with an incoming web hook). I would be happy to tell you more about this and share snippets
For quick and dirty integrations or integrations that are less time critical we use Zapier and IFTTT