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Environment Variable Validation

Using a schema validation library like zod lets us validate if all environment variables are set correctly.

Since Nuxt reads the environment variables at build time from the local .env file, you can validate them in a prepare script:

// `server.prepare.ts`
import { z } from 'zod'
import { defineNuxtPrepareHandler } from 'nuxt-prepare/config'

export default defineNuxtPrepareHandler(() => {
  const schema = z.object({
    NUXT_PUBLIC_FOO: z.string()

  const result = schema.safeParse(process.env)

  if (!result.success) {
    console.error(`Invalid environment variables:\n${ => `  - ${issue.path}: ${JSON.stringify(issue)}`).join('\n')

  return {
    ok: result.success

Released under the MIT License.