How to use .env variables in Nuxt 2 or 3?

Question

I have .env file in the project root, and in my nuxt config I am using variables to configure ReCaptcha like this:

import dotenv from 'dotenv'
dotenv.config()

export default {
    modules: [
        ['@nuxtjs/recaptcha', {
          siteKey: process.env.RECAPTCHA_SITE_KEY,
          version: 3,
          size: 'compact'
        }],
    ]
}

and in .env like this:

RECAPTCHA_SITE_KEY=6L....

but the application always failed with console log error:

ReCaptcha error: No key provided

When I hard-code ReCaptcha key directly like that: siteKey: 6L.... app start working, so I guess the problem is with reading .env props in nuxt.config

do you have any idea how to fix it?

EDIT: I tried update my nuxt.config by @kissu recommendation and by example which I found here: https://www.npmjs.com/package/@nuxtjs/recaptcha

so there is new nuxt.config which also not working:

export default {
    modules: [
       '@nuxtjs/recaptcha',
    ],
    publicRuntimeConfig: {
       recaptcha: {
         siteKey: process.env.RECAPTCHA_SITE_KEY,
         version: 3,
         size: 'compact'
       }
  }
}

Answer 1

If your Nuxt version is 2.13 or above, you don't need to use @nuxtjs/dotenv or anything alike because it is already backed into the framework.

To use some variables, you need to have an .env file at the root of your project. This one should be ignored by git. You can then input some keys there like

PUBLIC_VARIABLE="https://my-cool-website.com"
PRIVATE_TOKEN="1234qwer"

In your nuxt.config.js, you have to input those into 2 objects, depending of your use case, either publicRuntimeConfig or privateRuntimeConfig:

export default {
  publicRuntimeConfig: {
    myPublicVariable: process.env.PUBLIC_VARIABLE,
  },
  privateRuntimeConfig: {
    myPrivateToken: process.env.PRIVATE_TOKEN
  }
}

Differences: publicRuntimeConfig can basically be used anywhere, while privateRuntimeConfig can only be used during SSR (a key can only stay private if not shipped to the browser).

A popular use case for the privateRuntimeConfig is to use it for nuxtServerInit or during the build process (either yarn build or yarn generate) to populate the app with headless CMS' API calls.

More info can be found on this blog post: https://nuxtjs.org/blog/moving-from-nuxtjs-dotenv-to-runtime-config/

---

• Then, you will be able to access it into any .vue file directly with

this.$config.myPublicVariable

• You access it into Nuxt's /plugins too, with this syntax

export default ({ $axios, $config: { myPublicVariable } }) => {
  $axios.defaults.baseURL = myPublicVariable
}

• If you need this variable for a Nuxt module or in any key in your nuxt.config.js file, write it directly with

process.env.PRIVATE_TOKEN

Sometimes, the syntax may differ a bit, in this case refer to your Nuxt module documentation.

// for @nuxtjs/gtm
publicRuntimeConfig: {
  gtm: {
    id: process.env.GOOGLE_TAG_MANAGER_ID
  }
},

---

PS: if you do use target: server (default value), you can yarn build and yarn start to deploy your app to production. Then, change any environment variables that you'd like and yarn start again. There will be no need for a rebuild. Hence the name RuntimeConfig!

Nuxt3 update

As mentioned here, you can use the following for Nuxt3

nuxt.config.js

import { defineNuxtConfig } from 'nuxt3'

export default defineNuxtConfig({
  publicRuntimeConfig: {
    secret: process.env.SECRET,
  }
}

In any component

<script setup lang="ts">
  const config = useRuntimeConfig()
  config.secret
</script>

In a composable like /composables/test.js as shown in this comment

export default () => {
  const config = useRuntimeConfig()
  console.log(config.secret)
}

---

Here is the official doc for that part.