SOTA Mobile Engineering

Expert-level rules for building new mobile apps and auditing existing ones. Mobile is unlike web or backend in three load-bearing ways, and every rule in this skill flows from them:

1. You cannot roll back a shipped binary. Users update on their own schedule; some never do. Every release is permanent for some cohort. Design for kill switches, forced updates, and servers that tolerate ancient clients.
2. The device is hostile territory. The attacker owns the hardware, can decompile the binary, and can read anything you store insecurely. Client-side checks are deterrents, not controls; enforcement lives on the server.
3. Resources are budgeted, not abundant. Main thread, battery, memory, radio, and background execution time are all rationed by the OS. Apps that overspend get janked, killed, or throttled.

Facts in this skill (OS versions, store policies, framework status) were verified against primary sources in June 2026. Mobile platforms move fast — when a specific deadline or version matters, re-verify against Apple/Google developer docs before relying on it.

BUILD mode

When creating or extending a mobile app: