Local Setup & Env Vars

Zeno uses environment variables for configuration across different environments.

Environment Files

.env                 # Default values (committed)
.env.local           # Local overrides (not committed)
.env.development     # Development-specific
.env.production      # Production-specific
.env.test            # Test-specific

Loading Order

Environment variables are loaded in this order (later overrides earlier):

.env
.env.local
.env.[NODE_ENV]
.env.[NODE_ENV].local

Next.js Variables

For Next.js apps, prefix public variables with NEXT_PUBLIC_:

# Server-only (secure)
DATABASE_URL=postgres://...
API_SECRET=secret123

# Browser-accessible
NEXT_PUBLIC_API_URL=https://api.example.com
NEXT_PUBLIC_APP_NAME=My App

TypeScript Support

Create a typed env file for autocomplete:

// env.ts
export const env = {
  DATABASE_URL: process.env.DATABASE_URL!,
  API_SECRET: process.env.API_SECRET!,
  NEXT_PUBLIC_API_URL: process.env.NEXT_PUBLIC_API_URL!,
}

Vitest Environment

Tests use .env.test and NODE_ENV=test:

// vitest.config.ts
import { loadEnv } from "vite"

export default defineConfig({
  test: {
    env: loadEnv("test", process.cwd(), ""),
  },
})

Turborepo

Pass environment variables to Turborepo tasks:

// turbo.json
{
  "globalEnv": ["NODE_ENV"],
  "tasks": {
    "build": {
      "inputs": ["$TURBO_DEFAULT$", ".env*"]
    },
    "e2e": {
      "passThroughEnv": ["PLAYWRIGHT_*"]
    }
  }
}

Security

Never commit secrets — Use .env.local for sensitive values
Use .gitignore — Ensure .env*.local is ignored
Validate at startup — Check required vars exist
Rotate credentials — Update secrets regularly

Example validation:

function validateEnv() {
  const required = ["DATABASE_URL", "API_SECRET"]
  for (const key of required) {
    if (!process.env[key]) {
      throw new Error(`Missing required env var: ${key}`)
    }
  }
}