Slack
Slack supports both regular Unicode character entries for emoji, as well as short alpha codes which are converted into an emoji image when posted.
Native emojis are not used on Slack, which defaults to using Apple emoji images and provides user-level preferences to choose from alternatives such as Google, Twitter or Emoji One.
The setting to change emoji style can be found under the Preferences option inside the Team menu.

Unicode 9 Emoji Mockups
Unicode 9.0 is under development, and we have created mockups for the emoji candidates. Want to use these for your own Slack team? Download this zip file to get started.

Slack Emoji Reactions
In addition to regular emoji use, reactions are also available.

Slack Emoticon Codes
The following codes convert emoticons into emoji images on Slack.
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