Guided Notes
Configuration & Environment Variables
Keeping secrets out of code, process.env, .env files, validating configuration at startup, environment-specific settings, and the twelve-factor approach.
Why environment variables
Slide 1 / 5Configuration differs between your laptop, staging and production: database URLs, API keys, ports, feature flags. Hard-coding them is dangerous: • secrets end up in Git history (and public repos get scanned by attackers within minutes), • changing a setting requires a code change and redeploy.
The twelve-factor app approach: store config in the environment. Node reads it from process.env.