Tic-tac-toe for Slack alternatives and competitors

I found an interesting solution for the problem of not having tic-tac-toe in Slack with the use of Slack Buttons. The app is Serverless and almost stateless running on AWS Lambda which costs me about $0.30AUD/month to support over 600 hard working Slack teams. Someone told me that Slack internship candidates are asked to make tic-tac-toe. 😂