# Environment Variables

Environment variables defined on the Keycloak server can be transferred to the theme. This allows for a degree of theme customization without necessitating a rebuild. This approach is particularly useful if multiple parties are reusing your theme. As an example, you can distribute a single .jar file to multiple customers, enabling them to modify certain aspect of the login page by defining specific environment variables.

Concretely the ide is to be able, if you start your Keycloak server like this:

<pre class="language-bash"><code class="lang-bash">docker run \
    -e KEYCLOAK_ADMIN=admin \
    -e KEYCLOAK_ADMIN_PASSWORD=admin \
<strong>    --env MY_ENV_VARIABLE='Value of my env variable' \
</strong>    -p 8080:8080 \
    docker-keycloak-with-theme
</code></pre>

To be able to access MY\_ENV\_VARIABLE value in your theme. (This is assuming you're using docker but for for Helm for example see [this](https://docs.keycloakify.dev/keycloakify/v9/importing-your-theme-in-keycloak#using-helm)).

To implement this you need to use [the extraThemeProperties build option](https://docs.keycloakify.dev/keycloakify/v9/build-options#extrathemeproperties) like so:

{% tabs %}
{% tab title="Vite" %}

<pre class="language-typescript" data-title="vite.config.ts"><code class="lang-typescript">import { defineConfig } from 'vite'
import react from '@vitejs/plugin-react'
import { keycloakify } from "keycloakify/vite-plugin";

export default defineConfig({
  plugins: [
    react(), 
    keycloakify({
<strong>      extraThemeProperties: [ 
</strong><strong>        "MY_ENV_VARIABLE=${env.MY_ENV_VARIABLE:default}"
</strong><strong>      ]
</strong>    })
  ],
})
</code></pre>

{% endtab %}

{% tab title="Webpack" %}

<pre class="language-json" data-title="package.json"><code class="lang-json">{
    "keycloakify": {
<strong>        "extraThemeProperties": [ 
</strong><strong>            "MY_ENV_VARIABLE=${env.MY_ENV_VARIABLE:default}"
</strong><strong>        ]
</strong>    }
}
</code></pre>

{% endtab %}
{% endtabs %}

Then you will be able to access the value of MY\_ENV\_VARIABLE with kcContext.properties.MY\_ENV\_VARIABLE. Example:

{% code title="login/Template.tsx" %}

```tsx
import { useEffect } from "react";
import { type TemplateProps } from "keycloakify/login/TemplateProps";
import type { KcContext } from "./kcContext";
import type { I18n } from "./i18n";

export default function Template(props: TemplateProps<KcContext, I18n>) {
    const { kcContext } = props;

    useEffect(() => {
        console.log(kcContext.properties.MY_ENV_VARIABLE);
    }, []);

    //...

}
```

{% endcode %}

You also probably want to provide mock values the variables for when you're developing your theme in Storybook:

<pre class="language-typescript" data-title="login/kcContext.ts"><code class="lang-typescript">import { createGetKcContext } from "keycloakify/login";

export const { getKcContext } = createGetKcContext({
  mockData: [ /* ... */],
<strong>  mockProperties: {
</strong><strong>    MY_ENV_VARIABLE: "Mocked value"
</strong><strong>  }
</strong>});

export const { kcContext } = getKcContext({
  // Uncomment to test the login page for development.
  //mockPageId: "login.ftl",
});

export type KcContext = NonNullable&#x3C;ReturnType&#x3C;typeof getKcContext>["kcContext"]>;
</code></pre>