Discriminator

The discriminator determines which defaults to use. Defaults to NODE_ENV when not specified.

Note: NODE_ENV is a Node.js runtime concern — libraries like React and Express change behavior based on its value, and it’s conventionally limited to development, production, and test. For selecting environment-specific defaults (local dev URLs, staging credentials, etc.), a dedicated variable like APP_ENV is a better fit. You can have NODE_ENV=production in both staging and production while using APP_ENV to distinguish between them.

export default defineConfig({
  schema: z.object({
    APP_ENV: z.enum(["local", "staging", "prod"]),
    API_URL: z.string().url(),
  }),
  discriminator: "APP_ENV",
  defaults: {
    local: {
      API_URL: "http://localhost:4000",
    },
    staging: {
      API_URL: "https://staging.api.example.com",
    },
    prod: {
      API_URL: "https://api.example.com",
    },
  },
});