Global variables (Env)

Project Settings exposes environment variables through the read-only global Env. Each variable has separate Development and Production string values.

Create a variable

1. Open Project Settings in the Project panel.
2. Select Environment variables.
3. Under Environment used for Preview and Build, choose Development.
4. Click Add variable, enter API_BASE_URL, and set its value to https://dev-api.example.com.
5. Switch the environment to Production and set the same variable to https://api.example.com. Switching environments changes which value is being edited; it keeps the other value.
6. Select the environment you want for Preview, then click Apply changes.
7. Save the project with Ctrl+S. Run Preview again to compile the selected values.

Names are unique and case-sensitive. Start with an uppercase letter and use uppercase letters, numbers, and underscores. For example, API_BASE_URL is valid; api-url is not. Use the remove action on the variable row to delete it, then apply and save.

Read values in code

Add an API Client named ApiClient1. In a page event, use the configured value:

const apiUrl = Env.API_BASE_URL;
ApiClient1.Connection.BaseURL = apiUrl;
Message(apiUrl);

Use Env.API_BASE_URL directly, without an import or this. Monaco suggests configured names and reports undeclared names. Env is read-only at runtime; edit the value in Project Settings and compile again to change the distributed setting.

Numbers and booleans

All values remain strings, including "25" and "false". Add PAGE_SIZE and ENABLE_REPORTS in Project Settings before using this example:

const pageSize = Number(Env.PAGE_SIZE);
if (!Number.isInteger(pageSize) || pageSize < 1) {
  throw new Error('PAGE_SIZE must be a positive integer.');
}
const reportsEnabled = Env.ENABLE_REPORTS === 'true';
console.log(pageSize, reportsEnabled);

Choose an explicit convention such as true/false. JavaScript treats every nonempty string, including "false", as truthy.

Preview and exported applications

The compiler includes the selected values in the application. Changing Project Settings after export requires a new export. They are visible in distributed JavaScript: use public URLs and feature settings here, and keep server credentials on the backend.

Other kinds of state

For a value that changes during use, declare a typed field on the page or reusable class. That field belongs to the instance. Use a shared Unit when several parts of the application need the same function; see Global functions. Env remains the configuration source for values selected before execution.

See Project settings for the other sections and Packages and libraries for installing dependencies.