.env- -

A .env (environment) file is a simple text file used to store environment variables in a key-value format. It's commonly used in software development to configure applications without hardcoding sensitive information (like API keys, database credentials, or environment-specific settings) into the source code.

  • Use secret management for production.
  • Limit file access.
  • Rotate secrets regularly and on breach.
  • Audit and scan repos for leaked secrets.
  • Treat .env.example as documentation, not a source of secrets.

    • When multiple dotenv-style files are used, libraries or frameworks typically define a precedence order. Examples:

    # Database configuration
DB_HOST=localhost
DB_PORT=5432
DB_USER=admin

    config/production.env

    Or, use naming without the dot prefix:

    env.production
env.development

    These files are less likely to be served statically because they lack the leading dot that triggers special web server rules.

    | Method | Pros | Cons | Use Case | |--------|------|------|----------| | .env file | Simple, developer-friendly, language-agnostic | On-disk, not rotation-friendly, can be leaked | Local development, small projects | | System environment variables | Native, secure (if managed well) | Hard to manage across many variables, no file portability | Production (Docker, PaaS) | | Config files (JSON/YAML/TOML) | Structured, typed | Requires parsing code, can still leak if committed | Complex app config (non-secret) | | Secrets manager | Highly secure, auditable, rotated easily | Overhead, cost, requires network call | Production, large teams, compliance (HIPAA, SOC2) | Use secret management for production

  • Restrict file permissions.

  • Secrets rotation: Environment variables (including those from .env) can be inspected by processes running under the same user. For production, consider dedicated secrets managers (HashiCorp Vault, AWS Secrets Manager, Azure Key Vault) instead of .env files. Limit file access

    • .env files (often named .env) store environment variables for applications—configuration values like API keys, database URLs, feature flags, secrets, and environment-specific settings. They let you separate configuration from code so the same codebase can run in development, staging, and production with different values.

    Key benefits: