Using environment variables

Astro uses Vite’s built-in support for environment variables, and lets you use any of its methods to work with them.

Note that while all environment variables are available in server-side code, only environment variables prefixed with PUBLIC_ are available in client-side code for security purposes.

SECRET_PASSWORD=password123
PUBLIC_ANYBODY=there

In this example, PUBLIC_ANYBODY (accessible via import.meta.env.PUBLIC_ANYBODY) will be available in server or client code, while SECRET_PASSWORD (accessible via import.meta.env.SECRET_PASSWORD) will be server-side only.

Astro includes a few environment variables out-of-the-box:

• import.meta.env.MODE: The mode your site is running in. This is development when running astro dev and production when running astro build.
• import.meta.env.PROD: true if your site is running in production; false otherwise.
• import.meta.env.DEV: true if your site is running in development; false otherwise. Always the opposite of import.meta.env.PROD.
• import.meta.env.BASE_URL: The base url your site is being served from. This is determined by the base config option.
• import.meta.env.SITE: This is set to the site option specified in your project’s astro.config.
• import.meta.env.ASSETS_PREFIX: The prefix for Astro-generated asset links if the build.assetsPrefix config option is set. This can be used to create asset links not handled by Astro.

Use them like any other environment variable.

const isProd = import.meta.env.PROD;
const isDev = import.meta.env.DEV;

Environment variables can be loaded from .env files in your project directory.

You can also attach a mode (either production or development) to the filename, like .env.production or .env.development, which makes the environment variables only take effect in that mode.

Just create a .env file in the project directory and add some variables to it.

# This will only be available when run on the server!
DB_PASSWORD="foobar"
# This will be available everywhere!
PUBLIC_POKEAPI="https://pokeapi.co/api/v2"

For more on .env files, see the Vite documentation.

You can also add environment variables as you run your project:

POKEAPI=https://pokeapi.co/api/v2 npm run dev

POKEAPI=https://pokeapi.co/api/v2 pnpm run dev

POKEAPI=https://pokeapi.co/api/v2 yarn run dev

Instead of using process.env, with Vite you use import.meta.env, which uses the import.meta feature added in ES2020.

For example, use import.meta.env.PUBLIC_POKEAPI to get the PUBLIC_POKEAPI environment variable.

// When import.meta.env.SSR === true
const data = await db(import.meta.env.DB_PASSWORD);

// When import.meta.env.SSR === false
const data = fetch(`${import.meta.env.PUBLIC_POKEAPI}/pokemon/squirtle`);

When using SSR, environment variables can be accessed at runtime based on the SSR adapter being used. With most adapters you can access environment variables with process.env, for the Deno adapter you have to use Deno.env.get(). Cloudflare has its own way of handling environment variables. Astro will check the server environment for variables, if they don’t exist, Astro will look for them in .env files.

By default, Astro provides type definition for import.meta.env in astro/client.d.ts.

While you can define more custom env variables in .env.[mode] files, you may want to get TypeScript IntelliSense for user-defined env variables which are prefixed with PUBLIC_.

To achieve this, you can create an env.d.ts in src/ and configure ImportMetaEnv like this:

interface ImportMetaEnv {
  readonly DB_PASSWORD: string;
  readonly PUBLIC_POKEAPI: string;
  // more env variables...
}

interface ImportMeta {
  readonly env: ImportMetaEnv;
}