Environment Variables

Key-value pairs in the operating system that are used to store information about the environment that the system is running in.

Environment variables are key-value pairs set in the operating system or runtime environment that configure application behavior without hardcoding values in source code. They are used to store configuration such as database connection strings, API keys, feature flags, and service URLs.

Environment variables follow the twelve-factor app methodology, which recommends strict separation of configuration from code. This allows the same application code to run in different environments (development, staging, production) with different configurations. Sensitive values like secrets and credentials should be stored as environment variables rather than committed to source control.

In serverless platforms, environment variables are configured through the platform's interface or deployment configuration. Cloudflare Workers uses "secrets" and "vars" in the wrangler.toml configuration file. API gateways and serverless functions commonly use environment variables to store backend service URLs, authentication tokens for upstream services, and feature toggles that control routing or processing behavior.