The intantness of chat apps has always been a mystery to me.
The technical details of moving emojis through The Internet Pipes and across continents in 0.004 miliseconds is well beyond my paygrade.
Turns out it's not magic, but instead done through websockets. Which are like little portals that hold open a consistent connection between two machines.
I obviously still haven't a clue what goes on inside that dark little portal. Thankfully using tools like Vue & Socket.io save us from that level of depth.
A high-res & printable version of the sketchnote, plus the full course is avaliable here on the Vue and Socket.io for Real-Time Communication page.