Day 35 / 100 · How software works

Settings outside the code.

Secrets and settings that change between your laptop and the live site live in environment variables, not in your code.

The Secret File

# .env · on your machine only
DATABASE_URL=postgres://…
WEATHER_API_KEY=sk_live_…
SMTP_PASSWORD=…

# .gitignore · tells Git to skip it
.env

The Safe Template

# .env.example · safe to commit
DATABASE_URL=
WEATHER_API_KEY=
SMTP_PASSWORD=

# shows what's needed,
# never the values

Code is shared. Secrets are not.