These are the core objects you'll find throughout the platform — as part of Web API responses, Slash Command invocations, Message Button actions, and the events flowing through the RTM API & Events API.
|channel||A public channel|
|file||A file, snippet or post uploaded to Slack|
|group||A private group|
|im||A direct message channel with a user|
|mpim||A multiparty direct message|
|user||A member on your team|
|usergroup||A group of users, such as @marketing-team or @finance|