.env.development.local

.env.local .env.*.local

# .env.example (committed to the repository) REACT_APP_API_BASE_URL= REACT_APP_GOOGLE_MAPS_API_KEY= DATABASE_URL=postgresql://user:password@localhost/db NEXT_PUBLIC_ANALYTICS_ID=

This gives you:

To truly understand the role of .env.development.local , let’s visualize how a typical tool (like Create React App or Vite) resolves variables.

: Its primary role is to override default development settings without affecting other team members' environments. Development Only .env.development.local

How can I handle dev and testing environment on a single machine?

Next.js automatically loads environment variables from .env.development.local when you run next dev . Variables intended for the server look like: SECRET_KEY=123 and flexibility across different deployment stages.

Environment variables are key-value pairs used to configure applications without hardcoding values into the source code. They typically store database connection strings, API keys, authentication secrets, feature flags, and service endpoints. The Twelve-Factor App methodology advocates for storing configuration in the environment to maintain portability, security, and flexibility across different deployment stages.