Staff architecture · Mobile architecture
Controlled Change
Architecture, reliability, and evolution for mobile systems
Decide which boundary is worth its cost, and change a mobile system repeatedly without losing control of correctness, delivery speed or cost.
505 pages · 61 chapters in 8 parts · 9 appendices · 74 diagrams
Mike Salari · Staff mobile engineer · 500+ technical interviews from the hiring side
Secure checkout on Gumroad.Instant PDF and EPUB download.Lifetime updates.
What is inside
Controlled Change in its own order: what each part teaches, so you can see whether it covers the round you have next.
- 01
Part I: Decision discipline
Controlled change, why mobile is different, budgets and evidence, the economics of abstraction, ADRs and revisit triggers, and product stages.
- 02
Part II: Features and state
Screen to feature, dependency direction, domain-driven boundaries, state ownership, the pattern laboratory, navigation and restoration, and composition and injection.
- 03
Part III: Data under failure
Swift concurrency, Kotlin coroutines, process death, data authority, cache and freshness, offline-first, sync engines, conflicts and idempotency, version skew and real time.
- 04
Part IV: Scale, code, and teams
Feature modules, the module graph, modularisation gone wrong, ownership, build feedback, platform engineering, cross-platform, SDKs and legacy migration.
- 05
Part V: Production systems
Testing the failure model, performance, observability, security and privacy, accessibility, release architecture, flags and kill switches, and server-driven UI.
- 06
Part VI: AI-native
The AI-native stack, on-device and cloud routing, context and RAG, agents and tools, and model lifecycle and evaluation.
- 07
Part VII: Staff practice
Architecture reviews, fitness functions and debt, RFCs and roadmaps, incident-led architecture, system design interviews and replaceable systems.
- 08
Part VIII: Casebook
Atlas from prototype to platform, then nine cases: an offline field operation, a global checkout, messaging, regulated finance, a cross-platform rewrite, an AI trip operator, a mobile platform program, the agent in the engineering loop and the imposed decision.
Is it the right book for you?
Who gets the most from it, and when a different book is the better use of your time. The last list is as important as the first.
Use it when
- You can already build a mobile app: you have shipped features, fixed the crash, argued about MVVM in a pull request.
- You decide which boundary is worth its cost, and which migration can run without stopping the release train.
- You want decisions that will still be defensible in three years, when the person who made them has left.
- You are a Staff or Principal mobile engineer, a mobile architect, a platform lead, or the engineering manager who funds their decisions.
Skip it when
- You are learning your first architecture.
- You want a code walk-through that teaches dependency injection from scratch.
- You want a folder template to copy.
- You want one framework crowned as the answer.
By level
- Senior
- You have shipped features and now have to defend why a boundary is worth its cost.
- Staff
- Architecture reviews, RFCs, fitness functions and debt, and incident-led architecture in Part VII.
- Architect
- Release architecture, platform engineering, SDKs, legacy migration and the casebook, where several architectures stay defensible if their assumptions are explicit.
What a page looks like
Read Part I in order to get the decision tools. After that, start from the pressure in front of you: state and authority, offline sync, version skew, modularisation, release control or AI on mobile. The casebook follows Atlas, a fictional marketplace and field-operations product, from a two-engineer prototype to a multi-team platform.
The facts
- 505 pages
- 61 chapters in 8 parts
- 9 appendices
- 74 diagrams
- Nine-case casebook
- PDF and EPUB
- Last updated October 2026
- Levels: senior, lead, staff, architect
Five placements that define a mobile architecture
Five placements that define a mobile architecture
- 01Boundary
Boundary: which changes are allowed to propagate?
- 02Ownership
Ownership: who may mutate a piece of state, schema, module or release control?
- 03Authority
Authority: which representation wins when local intent, cached data, backend state and optimistic UI disagree?
- 04Lifetime
Lifetime: how long may work or state exist, from view lifetime to account lifetime?
- 05Evidence
Evidence: how will the team know whether a decision works in the field?
Questions buyers ask
Short answers about Controlled Change, from the book itself and the store page.
What is Controlled Change about?
A mobile architecture book for staff and principal mobile engineers, mobile architects and platform leads. It treats Clean Architecture, MVVM, MVI, Redux, TCA, VIPER, RIBs and feature modules as responses to pressure, not destinations, and is written in pressure order around Atlas, a fictional marketplace app.
How long is it?
505 pages, 61 chapters in 8 parts, 9 appendices and 74 diagrams, in PDF and EPUB, including a nine-case casebook.
Is it an iOS or an Android architecture book?
Both. The iOS and Android implementations stay native where platform mechanics matter, and Swift concurrency and Kotlin coroutines each get a chapter. Kotlin Multiplatform, React Native and Flutter are treated as boundaries of shared code.
Does it cover offline-first and sync?
Yes. Part III, Data under failure, covers process death and background work, data authority, cache and freshness, offline-first as a product decision, building a sync engine, conflicts, idempotency and reconciliation, schema evolution and version skew, and real-time events.
Does it cover AI on mobile?
Yes. Part VI covers on-device, cloud and hybrid routing, context and RAG, agents and tools, and model lifecycle and evaluation.
Can I read a sample?
Yes. A free sample is linked from this page: 12 pages for desktop and 16 pages for your phone. It is the field guide When the response never comes back.
What are the editions?
Book is the book alone, PDF and EPUB with lifetime updates. Pro adds the Atlas reference system: native iOS and Android, Kotlin Multiplatform, backend and contract code. Extended adds React Native, Flutter and the sync simulator that injects duplicate events, reordered writes, process death and model failure. Prices are $199, $299 and $399 on Gumroad.
How is it different from Mobile System Design Blueprint and Altitude?
Mobile System Design Blueprint is practice: decision chapters, system scenarios and exercises with answer keys. Altitude is staff systems beyond the app: backend contracts, security, observability and incidents. Controlled Change is the architecture decisions inside the app across its whole life.
Is it for beginners?
No. It assumes you can already build and ship a mobile app, and starts where architectural judgement becomes the harder problem.
Where is it sold?
On Gumroad, at the price shown there (From $199 when this page was built). Gumroad handles payment, the receipt and the download.