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

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Nuxt 2 to Nuxt 3: Runtime Config

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 server/ portion of your app, you can use useRuntimeConfig without any import.

Read more about runtime config.

Migration

1. Add any environment variables that you use in your app to the runtimeConfig property of the nuxt.config file.
2. Migrate process.env to useRuntimeConfig throughout the Vue part of your app.

Example

::code-group

import { defineNuxtConfig } from 'nuxt'

export default defineNuxtConfig({
  runtimeConfig: {
    // Private config that is only available on the server
    apiSecret: '123',
    // Config within public will be also exposed to the client
    public: {
      apiBase: '/api'
    }
  },
})

<script setup>
  const config = useRuntimeConfig()
  
  // instead of process.env you will now access config.public.apiBase
  console.log(config.public.apiBase)
</script>

const config = useRuntimeConfig()

export default (req, res) => {
  // In server, you can now access config.apiSecret, in addition to config.public
  console.log(config.apiSecret)
  console.log(config.public.apiBase)
}

# Runtime config values are automatically replaced by matching environment variables at runtime
NUXT_API_SECRET=api_secret_token
NUXT_PUBLIC_API_BASE=https://nuxtjs.org

::