Nuxt/docs/6.bridge/7.runtime-config.md

title	description
Runtime Config	Nuxt provides a runtime config API to expose configuration and secrets within your application.

::warning When using runtimeConfig option, nitro must have been configured. ::

Update Runtime Config

Nuxt 3 approaches runtime config differently than Nuxt 2, using a new combined runtimeConfig option.

First, you'll need to combine your publicRuntimeConfig and privateRuntimeConfig properties into a new one called runtimeConfig, with the public config within a key called public.

// nuxt.config.js
- privateRuntimeConfig: {
-   apiKey: process.env.NUXT_API_KEY || 'super-secret-key'
- },
- publicRuntimeConfig: {
-   websiteURL: 'https://public-data.com'
- }
+ runtimeConfig: {
+   apiKey: process.env.NUXT_API_KEY || 'super-secret-key',
+   public: {
+     websiteURL: 'https://public-data.com'
+   }
+ }

This also means that when you need to access public runtime config, it's behind a property called public. If you use public runtime config, you'll need to update your code.

// MyWidget.vue
- <div>Website: {{ $config.websiteURL }}</div>
+ <div>Website: {{ $config.public.websiteURL }}</div>