Learn Pinia - Latest Stable Features (v4.x)

#Introduction

Technology never stops, and neither does Pinia. Heading into its latest release, the Pinia team keeps refining types, compatibility with the latest Vue, and its supporting ecosystem. Episode 20 maps the state of Pinia v4 and the 2026 ecosystem.

Episode 20 covers the latest stable features: what changed in Pinia v4.x, Vue 3.5+ compatibility, and the position of supporting libraries like @pinia/nuxt, @pinia/testing, and Pinia Colada.

#What's New in Pinia v4.x

Pinia v4.0.x was released in July 2026 as a major update bringing comprehensive improvements:

• Type improvements: more accurate inference and generic compatibility, especially for Setup stores and plugins.
• Vue 3.5+ compatibility: leverages Vue's latest reactivity without changing the Pinia API.
• @pinia/nuxt 1.x integration: smoother module setup with the latest Nuxt.

One of the most noticeable improvements is type inference on Setup stores. Look at the example of state and getter in a single definition:

Type inference in a Setup store

export const useThemeStore = defineStore('theme', () => {
  const mode = ref<'light' | 'dark'>('light')
  const isDark = computed(() => mode.value === 'dark')
  return { mode, isDark }
})

In v4, ref<'light' | 'dark'> is inferred automatically by TypeScript, so you don't need to write the generic defineStore<string, ...> explicitly. As a result, store.mode and store.isDark are correctly typed in components — the editor gives autocomplete and errors from the moment you write, not at runtime. This improvement is felt most in projects that write many Setup stores.

The key point: Pinia's core API — defineStore, createPinia, storeToRefs — stays stable. Upgrading to v4 doesn't require rewriting the stores you learned in episodes 0-19.

npm view pinia version
npm view @pinia/nuxt version

npm view pinia version and npm view @pinia/nuxt version show the latest versions in the registry. This verification is important before upgrading so the documentation you read matches the version.

#Vue 3.5+ Compatibility

Pinia v4 is designed on top of Vue 3.5+, which brings reactivity performance improvements and better type support. What you need to know:

• ref and reactive work as usual — no store syntax changes.
• Upgrade Pinia to v4 together with Vue to 3.5+ for the best results.
• All the patterns in this series remain valid without modification.

Because backwards compatibility is maintained, projects on Vue 3.4 can generally upgrade without breaking — but the officially recommended combination is Vue 3.5+ with Pinia v4.

#Migrating from v3 to v4

Migration is generally as easy as changing the version in package.json and running npm i. There's no rename command like when Vue 2 moved to Vue 3; the only areas to watch are those related to types:

The same store in v3 and v4

// v3 and v4 accept this code without changes
export const useUserStore = defineStore('user', {
  state: () => ({
    profile: null as Profile | null,
  }),
  getters: {
    isLoggedIn: (state) => state.profile !== null,
  },
})

null as Profile | null still works in v4 thanks to better generic inference. In older releases, generic combinations like defineStore<string, State, Getters, Actions> sometimes forced writing all four parameters explicitly; in v4 those parameters are inferred automatically, so store code feels more concise.

Recommended migration steps:

• Back up the branch before upgrading.
• Update Vue to 3.5+ and Pinia to 4.x at the same time.
• Run bun run typecheck and resolve all errors.
• Run the test suite — especially store tests with @pinia/testing.

If all tests are green and there are no type errors, the migration is practically done. The remaining time is best spent exploring type improvements that allow simplifying store code.

#The 2026 Ecosystem

Three supporting libraries are now stable and have become standard:

• @pinia/nuxt 1.0.x: the official Nuxt module — auto-setup of Pinia, automatic hydration (episode 11).
• @pinia/testing 2.x: testing utilities with createTestingPinia (episode 17).
• Pinia Colada: async server state, now stable — fetching, caching, and deduplication (episode 14).

pinia: 4.0.2
@pinia/nuxt: 1.0.1
@pinia/testing: 2.0.x

All three work together: Nuxt for SSR, testing for quality, and Colada for server state. This is the complete Pinia stack in 2026.

#Closing

Episode 20 maps the current state of Pinia. You now know what changed in Pinia v4.x, why Vue 3.5+ is the recommended pairing, and the position of the three supporting libraries that are now stable: @pinia/nuxt, @pinia/testing, and Pinia Colada.

Key takeaways:

• Pinia v4.0.x (July 2026) brings type improvements and Vue 3.5+ compatibility.
• Pinia's core API stays stable — upgrade without rewriting stores.
• @pinia/nuxt 1.x simplifies Nuxt integration.
• @pinia/testing 2.x and Pinia Colada are now stable.
• Verify versions with npm view before upgrading.
• The 2026 stack: Pinia + Nuxt + testing + Colada for server state.

In the next episode, episode 21, we'll discuss production-ready architecture — store architecture for team scale, naming and documentation conventions, using Vue Query or Colada for server state, and production quality: type-check, lint, test coverage, monitoring, and bundle size.