Design a portfolio and watchlist screen where hundreds of symbols change price dozens of times a second. Focus on how you control the UI refresh rate.
WebSocket messages are coalesced into latest values in an actor and pushed to the UI once every 100 to 250ms. Cells update partially with reconfigure, the subscription drops when the app goes to the background, and on return you sync with a REST snapshot before resubscribing.
iOS system designMultiple choiceBasics
A stock app needs a watchlist screen (prices updating several times a second in the…
#realtime #websocket
iOS system designShort answerAdvanced
You're adding an online/offline/last seen indicator to a contact list. Given that the app…
#websocket #battery
iOS system designShort answerAdvanced
A real-time social news feed receives incremental WebSocket events and an initial REST…
#realtime #websocket
iOS system designShort answerAdvanced
Design an infinite-scroll feed screen like Twitter's from the iOS client's point of view…
#realtime