.env.development (2026)

: Avoid writing KEY = value . Write KEY=value instead.

.env.development is a file used to store environment variables specific to the development environment. It is a variation of the popular .env file, which is used to store environment variables for different environments. The .env.development file is typically used in conjunction with other .env files, such as .env.test , .env.staging , and .env.production , to manage environment-specific variables. .env.development

Mistakes in environment variable management represent a leading cause of security breaches and credential leaks. Implement the following strategies to safeguard your application. Never Commit Sensitive Files to Version Control : Avoid writing KEY = value

The .env.development file serves a similar purpose, but with a twist. While the .env file is typically used across multiple environments (e.g., development, staging, production), .env.development is specifically designed for your development environment. It is a variation of the popular

Implementation notes (concise)

: It allows developers to define variables (like a local database URL or a mock API key) that are automatically loaded when running commands like npm run dev .

Frameworks like Next.js and Vite follow a specific priority order when loading variables. A typical lookup order looks like this (from highest priority to lowest):