Design the iOS client for a 1:1 chat like WhatsApp. Focus on message ordering, duplicates, and the offline send queue.
The local DB is the single source of truth and messages are sent idempotently with a client-generated UUID. Order is settled by a server sequence number, offline sends go through an outbox queue with background retry, and media is uploaded separately with only the URL carried in the message.
iOS system designShort answerAdvanced
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iOS system designMultiple choiceBasics
A stock app needs a watchlist screen (prices updating several times a second in the…
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iOS system designShort answerAdvanced
Design a portfolio and watchlist screen where hundreds of symbols change price dozens of…
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