Focus on your users. If they want to do silly things like gifs or reactions give it to them.
I am working on a website where I would like to implement live chat for users(ala fb messenger). What are some good tips on designing it from structural and technological side of things?
PS: for now, there won't be multi-user chats(slack/discord), only one-to-one.
(for some reason the info got stripped so I have to comment).
Managing persistent connections will be a challenge, especially at high scale. Choose your architecture wisely. You'll end up with a sticky session system.