Thinking through system design for mobile engineers
Notes on how I think about mobile systems, product behavior, and high-level architecture. · 9 min read
Series
System design for mobile engineers
I’m working through mobile system design from the client side of the product. Most examples start with backend services. I care more about the parts that get messy on a phone: local state, sync, push, offline behavior, product quality, APIs, and who owns what between client and server.
Start with the overview if you want context, or jump into the app you’re interested in. I’ll keep adding cases as I write them.
Suggested path
Read in order, or jump around.
- 01Start
- 07
Design a spoken English practice app for mobile engineers
A system design pass for TalkLooper, a spoken English practice app: why the first MCP version was elegant, why transcript-only analysis broke down, and how I would redesign the loop around raw audio, consent, speech events, and practice feedback. · 16 min read
Quizzes
Quick checks
Use these after a post, or before one if you want to test yourself first.
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Slack mobile design quiz
12 Q · ~9 minCheck the Slack mobile design post: product behavior, sync, push, local state, and scaling tradeoffs.
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Slack client architecture quiz
12 Q · ~9 minCheck the Slack client architecture post: local truth, state ownership, outbox, push routing, offline UX, accessibility, and client observability.
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PayPal mobile design quiz
12 Q · ~9 minCheck the PayPal mobile design post: payment intents, ledgering, idempotency, risk, webhooks, local state, and recovery flows.
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Robinhood mobile design quiz
12 Q · ~9 minCheck the Robinhood mobile design post: quote freshness, order idempotency, fills, buying power, ledgers, notifications, security, and mobile failure modes.
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Prism mobile design quiz
8 Q · ~6 minCheck the Prism mobile design post: local-first play, daily seeds, sync, leaderboards, streaks, notifications, and mobile reliability.
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Spoken English practice app design quiz
8 Q · ~6 minCheck the spoken English practice app system design post: MCP boundaries, raw audio, speech events, consent, analysis, feedback, and mobile reliability.
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Android LLM client architecture quiz
12 Q · ~9 minA short practice quiz for the Android LLM client architecture post, focused on local versus remote inference, streaming state, context, memory, privacy, cost, and mobile failure modes.