Design Instagram Stories: photos and short videos that vanish after 24 hours, tap left or right to advance, and a seen indicator. Focus on the media loading that makes the next story appear the instant you tap.
The story tray fetches only per-user bundle metadata, then preloads the current item plus the next 1 or 2. Video gets fast first frames through an AVPlayer instance pool and HLS, and expiry is filtered on the client against server time.
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