kp-flow-cold-vs-hot

One-line summary

Flow is cold (re-runs per collector), SharedFlow is hot and broadcast (no required current value, optional replay), StateFlow is hot and conflates (always has a current value). Pick by what the consumer needs: a fresh execution, an event stream, or current state.

When to use this skill

• Designing an API that exposes a stream of values.
• Refactoring callback-based code into a coroutines-friendly stream.
• Confusion between which Flow variant to use for a given use case (UI state, server-sent events, periodic polling, etc.).

When NOT to use this skill

• A single async value — use suspend fun or Deferred<T>.
• A bounded list of values that's available all at once — use List<T> or Sequence<T>.

Core content

Flow<T> — cold. Lazy by construction; the producing code runs only when a collector starts collecting, and re-runs from scratch for each new collector. Each collector gets its own independent run.