Validate environment variables with type safety using Zod

Create env.ts file and define schema with necessary ENV variables

// file: env.ts
import { z } from "zod";

const envSchema = z.object({
  POSTGRES_URL: z.string().url(),
  POSTGRES_PRISMA_URL: z.string().url(),
  POSTGRES_USER: z.string().min(1),
  POSTGRES_HOST: z.string().min(1),
  POSTGRES_PASSWORD: z.string().min(1),
  POSTGRES_DATABASE: z.string().min(1),
  ENV: z.union([z.literal("development"), z.literal("test"), z.literal("production")]),
});

// Validate `process.env` using the schema
const env = envSchema.parse(process.env);

export default env;

Code IntelliSense when using env

Extend Global ProcessEnv

Extend the global process.env with envSchema to access variables on process.env:

declare global {
  namespace NodeJS {
    interface ProcessEnv extends z.infer<typeof envSchema> {}
  }
}

Caveat: Process.env variables are always strings, even if variable in envSchema maybe defined as a number.