MVI Pattern

ARCHITECTURE › Patterns

Single immutable state per screen, intents in, a reducer producing new state.

MVI comes up whenever interviewers probe how you tame complex screen state and make UI updates predictable. They test whether you can articulate unidirectional data flow with one immutable state object, how intents flow through a reducer, and whether you can weigh MVI's debuggability against its boilerplate versus plain MVVM. Expect to defend when MVI is worth the ceremony and how you handle side effects within it.

What this covers

• Defining a single immutable state data class per screen and why immutability matters
• Modeling user actions as Intent/Event objects and routing them through one entry point
• Writing a pure reducer: (currentState, intent) -> newState, and why it eases testing
• Explaining time-travel debugging and explicit, replayable state transitions
• Comparing MVI vs MVVM and judging when the extra boilerplate pays off
• Handling side effects and one-off events without breaking unidirectional flow

Study this topic

• MVI Pattern explained: the guided lesson
• 14 practice quiz questions
• 9 revision flashcards
• MVI Pattern interview questions and answers

Further reading

• UI layer (UDF/state)
• Architecture recommendations