Env Variables and Modes

    • import.meta.env.MODE: {string} the mode the app is running in.

    • import.meta.env.BASE_URL: {string} the base url the app is being served from. In development, this is always /. In production, this is determined by the .

    • import.meta.env.PROD: {boolean} whether the app is running in production.

    During production, these env variables are statically replaced. It therefore necessary to always reference them using the full static string. For example, dynamic key access like import.meta.env[key] will not work.

    It will also replace these strings appearing in JavaScript strings and Vue templates. This should be a rare case, but it can be unintended. There are ways to work around this behavior:

    • For Vue templates or other HTML that gets compiled into JavaScript strings, you can use the <wbr> tag, e.g. import.meta.<wbr>env.MODE.

    Vite uses to load additional environment variables from the following files in your project root:

    Loaded env variables are also exposed to your client source code via import.meta.env.

    To prevent accidentally leaking env variables to the client, only variables prefixed with VITE_ are exposed to your Vite-processed code. e.g. the following file:

    Only VITE_SOME_KEY will be exposed as import.meta.env.VITE_SOME_KEY to your client source code, but DB_PASSWORD will not.

    SECURITY NOTES

    By default, the dev server (serve command) runs in development mode, and the build command runs in production mode.

    This means when running vite build, it will load the env variables from .env.production if there is one:

    In your app, you can render the title using import.meta.env.VITE_APP_TITLE.

    However, it is important to understand that mode is a wider concept than just development vs. production. A typical example is you may want to have a “staging” mode where it should have production-like behavior, but with slightly different env variables from production.

    You can overwrite the default mode used for a command by passing the option flag. For example, if you want to build your app for our hypothetical staging mode:

    Now your staging app should have production-like behavior, but displaying a different title from production.