Large-Scale Mobile System Architecture Questions

End to end architecture and design of mobile systems at scale covering client side patterns server side services and operational practices. Topics include application programming interface design for mobile constraints, client side caching and offline synchronization, server side service decomposition and data stores, caching layers and content delivery strategies, personalization and recommendation pipelines, consistency models and conflict resolution strategies, real time and streaming features, resiliency and backpressure handling, monitoring and operational runbooks, and trade off analysis across latency throughput consistency and cost.