Nuxt/docs/content/3.docs/3.migration/8.runtime-config.md

Runtime Config

If you wish to reference environment variables within your Nuxt 3 app, you will need to use runtime config.

When referencing these variables within your components, you will have to use the useRuntimeConfig composable in your setup method (or Nuxt plugin). In the Nitro portion of your app, you can import directly from #config.

Read more about runtime config.

Migration

1. Add any environment variables you use in your app to your publicRuntimeConfig or privateRuntimeConfig.
2. Migrate process.env to useRuntimeConfig throughout the Vue part of your app.

Example

::code-group

import { defineNuxtConfig } from 'nuxt3'

export default defineNuxtConfig({
  publicRuntimeConfig: {
    BASE_URL: process.env.BASE_URL || 'https://nuxtjs.org'
  },
  privateRuntimeConfig: {
    // variables that can only be accessed on server-side
  },
})

<script setup>
  const config = useRuntimeConfig();
  // instead of process.env.BASE_URL you will now access config.BASE_URL
</script>

import config from '#config';

export default (req, res) => {
  // you can now access config.BASE_URL
  return {
    baseURL: config.BASE_URL
  }
}

::