Reflex vs Redux/Zustand: A Comprehensive Comparison

This guide compares Reflex with popular state management solutions like Redux and Zustand, highlighting architectural differences.

Comparison Table

	Redux / Zustand	Reflex
Type / Role	Libraries providing low-level primitives for state management — architecture must be assembled manually	Complete framework with opinionated patterns and conventions	Framework: predefined architecture eliminates decision fatigue, enforces consistency, and provides scalable, battle-tested patterns
Architecture Clarity	Redux: Complex action/reducer/middleware layers. Zustand: Simple but unstructured for large apps	Event-driven architecture with explicit separation of events, state updates, and effects	Unified mental model: single event→effect→subscription pipeline simplifies reasoning and maintenance in large systems
State Derivation / Selectors	Redux: Reselect for memoized selectors. Zustand: Manual selector functions	Reactive subscriptions with automatic dependency tracking	Declarative data flow: dependencies tracked automatically; no manual selector logic or stale closure issues common in hook-based stores
Side-effects Handling	Redux: Middleware (thunks/sagas) mixes effects with business logic. Zustand: Inline or custom middleware	Pure events return effects as declarative data structures	Pure business logic: events stay pure, effects are explicit and testable; tooling can visualize and validate effect flow
Reactive Updates	Redux: connect/selectors trigger re-renders. Zustand: Manual subscription control	Built-in reactive subscription system	Automatic granularity: reactivity graph ensures updates only when subscribed data changes — no manual optimization required
Debuggability / Traceability	Redux: DevTools track actions/state diffs. Zustand: Limited devtools	Built-in event tracing, db snapshots, and live dependency visualization (via Reflex DevTools)	Full-system X-ray: Reflex DevTools expose every event, effect, and reactive subscription in real time — allowing total control over application behavior, state flow, and even performance profiling
Testing / Reproducibility	Redux: Reducers are testable, but async and effects complicate tests. Zustand: unit tests only	Pure events and declarative effects allow full replay and snapshot testing	Deterministic replay: event logs reproduce complete app state, simplifying regression and snapshot testing
Scalability of Architecture	Redux: Scales with conventions and discipline. Zustand: Not structured for large teams	Composable interceptors and modular event/effect layers scale predictably	Team scaling: consistent patterns and guardrails reduce cognitive load and architectural drift in large teams
Language Safety / Immutability	Redux: Optional Immer or Immutable.js; mutable risk in plain JS. Zustand: Mutable by default	Immer ensures structural sharing and type-safe mutations	Type-safe immutability: compile-time safety with ergonomic mutation syntax and performance-efficient state updates

Key Architectural Differences

Event-Driven vs Store-Centric

Redux/Zustand: Focus on store mutations and selectors. Business logic is scattered across actions, reducers, and middleware.

Reflex: All state changes flow through events. Events are pure functions that mutate drafts and return effects as data.

// Redux with thunk
const fetchUser = (id) => async (dispatch) => {
  dispatch({ type: 'FETCH_START' })
  try {
    const user = await api.getUser(id)
    dispatch({ type: 'FETCH_SUCCESS', payload: user })
  } catch (error) {
    dispatch({ type: 'FETCH_ERROR', error })
  }
}

// Zustand with async actions
const useStore = create((set, get) => ({
  user: null,
  loading: false,
  fetchUser: async (id) => {
    set({ loading: true })
    try {
      const user = await api.getUser(id)
      set({ user, loading: false })
    } catch (error) {
      set({ error, loading: false })
    }
  }
}))

// Reflex
regEvent('fetch-user', ({ draftDb }, id) => {
  draftDb.loading = true
  return [
    ['http', {
      url: `/users/${id}`,
      onSuccess: ['user-loaded'],
      onFailure: ['fetch-failed']
    }]
  ]
})

Reactive Subscriptions vs Manual Selectors

Redux/Zustand: Components subscribe to store changes and use selectors to derive data.

Reflex: Components declare data dependencies through subscriptions. The system automatically tracks dependencies and optimizes updates.

// Redux with reselect
const selectFilteredItems = createSelector(
  state => state.items,
  state => state.filter,
  (items, filter) => items.filter(item => item.type === filter)
)

// Zustand with selectors
const useStore = create((set, get) => ({
  items: [],
  filter: 'all',
  filteredItems: () => {
    const { items, filter } = get()
    return items.filter(item => item.type === filter)
  }
}))

// Reflex
regSub('filtered-items',
  (items, filter) => items.filter(item => item.type === filter),
  () => [['items'], ['filter']]
)

Effects as Data vs Inline Logic

Redux/Zustand: Async logic mixed with business logic through middleware.

Reflex: Effects are pure data structures returned from events, enabling better composition and testing.

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