I have a workgroup that uses the Slack chatting app/website/destop version to communicate, and the desire to send usable mathematical expressions across to friends is something we'd like to do there. While it doesnt seem like there is any official implementation of LaTeX or a plugin for it there are many ways for DIY integration: 
I wanted to know how to get LaTeX rendering working on Slack, be it through integrations and/or customization of Slack and/or through web hooking. The only thing I'd prefer not to do is hook out to another website, make the render into a picture, and then hook it back into Slack.
Best Answer
I made a small script that installs MathJax in Slack's desktop client (basically the same solution as goatandsheep's, but with some Electron hacking). No server needed, supports both inline and display math, and equations can be edited.
https://github.com/fsavje/math-with-slack