Error: Environment variable not found: DATABASE_URL

What causes this

Prisma reads DATABASE_URL from your .env file (or system environment variables) to connect to your database. This error means it can’t find it. Common causes:

• No .env file exists in your project root
• The .env file exists but doesn’t contain DATABASE_URL
• The .env file is in the wrong directory (Prisma looks in the directory where you run the command)
• You’re running in a CI/CD environment where .env files aren’t deployed
• The variable name has a typo or extra whitespace

Fix 1: Create or fix your .env file

# .env (in project root, same level as package.json)
DATABASE_URL="postgresql://user:password@localhost:5432/mydb"

For different databases:

# PostgreSQL
DATABASE_URL="postgresql://user:password@localhost:5432/mydb"

# MySQL
DATABASE_URL="mysql://user:password@localhost:3306/mydb"

# SQLite
DATABASE_URL="file:./dev.db"

# MongoDB
DATABASE_URL="mongodb://user:password@localhost:27017/mydb"

Fix 2: Check the file location

Prisma looks for .env relative to where you run the command:

# Make sure you're in the project root
ls -la .env

# Check what's in it
cat .env | grep DATABASE_URL

If your .env is in a subdirectory, tell Prisma where to find it in schema.prisma:

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

Or specify a custom path:

# Use dotenv-cli to load from a specific file
npx dotenv -e .env.local -- npx prisma migrate dev

Fix 3: Set the variable in your shell

For one-off commands:

DATABASE_URL="postgresql://user:password@localhost:5432/mydb" npx prisma migrate dev

Or export it for the session:

export DATABASE_URL="postgresql://user:password@localhost:5432/mydb"
npx prisma migrate dev

Fix 4: Fix CI/CD environments

In CI, set environment variables through your platform’s settings, not .env files:

# GitHub Actions
env:
  DATABASE_URL: ${{ secrets.DATABASE_URL }}

# Vercel — set in project settings dashboard

# Docker
docker run -e DATABASE_URL="postgresql://..." myapp

Fix 5: Check for invisible characters

Sometimes copy-pasting introduces invisible characters:

# Check for hidden characters
cat -A .env | grep DATABASE_URL
# Should show: DATABASE_URL="..."$
# If you see ^M or other characters, recreate the file

How to prevent it

• Add .env.example to your repo with placeholder values so new developers know what variables are needed
• Use our .env file validator to check for common issues
• Never commit .env to git — add it to .gitignore
• In production, use your platform’s secrets management instead of .env files
• Check out our guide on environment variables for Next.js, Prisma, and Stripe

Related: Prisma: Migration Failed — Database Schema Drift

Related: Prisma P2002: Unique Constraint Failed — How to Fix It