📦 📦 90-Day Android/Kotlin/KMP Roadmap

📦 Frontend → Android/KMP Engineer transition. 90 days. 5 phases. From Kotlin basics to production-grade Kotlin Multiplatform apps.

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📌 How to use this template

• Work phases in strict order — every phase is a prerequisite for the next
• Daily ritual: study the concept → write code → break it intentionally → fix it → log one insight
• Use the Daily Tracker to stay accountable
• Open each Phase page for full breakdowns, projects, real-world references, and mistake corrections

💡 The #1 rule of Android/KMP engineering: The platform is the constraint. Understanding the Android lifecycle, the JVM memory model, and the Kotlin compiler internals is what separates engineers who fight the framework from engineers who use it correctly.

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🗺️ Roadmap at a glance

Phase	Days	Focus	Key Output
Phase 1 — Kotlin Foundations	Days 1–15	Language internals, coroutines, type system	Idiomatic Kotlin fluency
Phase 2 — Android Core	Days 16–35	Lifecycle, Jetpack, Compose, Navigation	Production Android app skeleton
Phase 3 — Architecture & Patterns	Days 36–55	MVI, Clean Architecture, DI, testing	Scalable, testable app architecture
Phase 4 — Kotlin Multiplatform	Days 56–75	KMP setup, shared logic, platform APIs, CMP	Shared business logic across Android + iOS
Phase 5 — Expert Android/KMP	Days 76–90	Performance, CI/CD, advanced Compose, production	Staff-level mobile engineering

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⚡ The Android/KMP Engineering Decision Framework

Ask these questions in order for every feature you build:

1. Where does this logic live? — shared module (pure Kotlin, no platform) or platform module?
2. Who owns the state? — ViewModel, Repository, or UI local state?
3. How does it survive configuration change? — ViewModel survives rotation. Composable state does not.
4. How does it survive process death? — SavedStateHandle or persistence layer.
5. How is it tested? — unit test (pure Kotlin), integration test (Android), or UI test (Compose)?
6. What is the threading model? — which coroutine dispatcher? Is it safe to call from the main thread?

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📊 My progress

• Current phase: Phase 1
• Current day: Day 1 of 90
• Apps shipped: 0
• KMP modules built: 0

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🔖 Quick links

• ☁️ Phase 1 — Kotlin Foundations
• 📱 Phase 2 — Android Core
• 🏗️ Phase 3 — Architecture & Patterns
• 🌐 Phase 4 — Kotlin Multiplatform (KMP)
• 🧠 Phase 5 — Expert Android/KMP

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💻 Tech stack this roadmap builds on

Layer	Technology
Language	Kotlin 2.x
UI (Android)	Jetpack Compose
UI (iOS via KMP)	Compose Multiplatform
Architecture	MVI + Clean Architecture
DI	Koin or Hilt
Async	Kotlin Coroutines + Flow
Networking	Ktor Client (KMP)
Local DB	SQLDelight (KMP) or Room (Android)
Build	Gradle Kotlin DSL + Convention Plugins
CI/CD	GitHub Actions + Fastlane
Testing	JUnit5, Turbine, Paparazzi, XCTest

📅 Android/KMP Daily Tracker