Add nuxt-socket-io dependency to your project:

yarn add nuxt-socket-io
npm install nuxt-socket-io

Then, add nuxt-socket-io to the modules section of nuxt.config.js:

  modules: [
  io: {
    // Options

In Nuxt3, Vuex is no longer shipped with it. You can consider using my nuxt3-vuex module to plug it in. If you wish to still use Vuex in Nuxt3 (not recommended), then you will also need at the minimum a Vuex state defined:

export const state = () => ({})

The module needs this so it can register its own Vuex module.

(NOTE: a new iox option is meant to sort of be a drop-in replacement)