Nanostores vs Zustand: Framework-Agnostic Atoms vs React Store

Overview

Nanostores is a tiny, framework-agnostic state management library optimized for minimal bundle size and multi-framework compatibility. It was created specifically to address the needs of multi-framework environments like Astro, where you might have React, Vue, and Svelte components on the same page that need to share state. Zustand is a minimal, hook-based state store primarily built for React, with a larger community and richer ecosystem.

The choice between them is primarily driven by your framework environment. For React-only or Next.js applications, Zustand is the more idiomatic and better-supported choice. For Astro sites, multi-framework microfrontends, or applications that need state accessible from multiple framework contexts, Nanostores provides genuine cross-framework value.

Key Technical Differences

Nanostores provides three primitives: atom() for a simple value store, map() for an object store where individual keys can be subscribed to independently, and computed() for derived values that automatically update when dependencies change. Framework integration is handled by adapter packages: @nanostores/react provides useStore, @nanostores/vue provides useStore for Vue 3, and so on. The core library has no framework dependency.

Zustand's create() function returns a React hook bound to a specific store. The hook handles subscriptions and re-renders automatically. While Zustand has a vanilla JS API (createStore in v5) for non-React contexts, its primary ergonomics are React-centric. Its middleware system (devtools, persist, immer) is mature and well-documented.

Nanostores' per-store size is remarkable — atom is around 115 bytes, map around 330 bytes, computed around 180 bytes. For applications that are extremely bundle-size conscious, this granularity means you pay only for what you use. Zustand at ~1KB is already very small, but Nanostores is an order of magnitude smaller.

Performance & Scale

Both libraries achieve efficient subscriptions. Nanostores' map store is particularly efficient: subscribing to a specific key means the subscriber only notifies on changes to that key, not the entire map object. This granularity can reduce unnecessary re-renders in components that use only part of a larger state object.

When to Choose Each

Choose Nanostores for Astro sites and any multi-framework environment. Its cross-framework compatibility is its defining feature, and for Astro's island architecture, having a shared state layer that works identically in React, Vue, and Svelte islands is uniquely valuable.

Choose Zustand for React-centric projects. The larger community, richer middleware ecosystem, DevTools integration, and idiomatic React API make it the better choice when framework diversity is not a concern.

Bottom Line

Nanostores wins for multi-framework environments and extreme bundle-size optimization. Zustand wins for React-focused applications with a richer ecosystem. Nanostores is the obvious choice for Astro; Zustand is the obvious choice for React/Next.js.