Kotlin Coroutines Flows

This covers the bread and butter of async Kotlin: structured concurrency patterns, Flow operators, StateFlow for UI state, and testing with runTest and Turbine. You get practical examples of parallel decomposition with async/await, combining multiple flows for complex UI state, and one-time events with SharedFlow. The anti-patterns section is honest about common mistakes like GlobalScope leaks and collecting flows in init blocks. Most valuable for Android or KMP developers who've moved past basic launch/async and need patterns for real app state management, like handling debounced search, retries with backoff, or keeping upstream flows alive through configuration changes with WhileSubscribed.

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last updated: Aug 21, 2026

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Install

$ npx -y skills add affaan-m/ecc --skill kotlin-coroutines-flows --agent claude-code

Installs into .claude/skills of the current project.

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Kotlin Coroutines & Flows

Patterns for structured concurrency, Flow-based reactive streams, and coroutine testing in Android and Kotlin Multiplatform projects.

When to Activate

Writing async code with Kotlin coroutines
Using Flow, StateFlow, or SharedFlow for reactive data
Handling concurrent operations (parallel loading, debounce, retry)
Testing coroutines and Flows
Managing coroutine scopes and cancellation

Structured Concurrency

Scope Hierarchy

Application
  └── viewModelScope (ViewModel)
        └── coroutineScope { } (structured child)
              ├── async { } (concurrent task)
              └── async { } (concurrent task)

Always use structured concurrency — never GlobalScope:

// BAD
GlobalScope.launch { fetchData() }

// GOOD — scoped to ViewModel lifecycle
viewModelScope.launch { fetchData() }

// GOOD — scoped to composable lifecycle
LaunchedEffect(key) { fetchData() }