2. APIs & Backend Design
Configuration, Environments & Secrets
Separate code from environment configuration and manage secrets without leaking them into repositories or clients.
Lesson overview
Configuration includes URLs, feature flags, timeouts and credentials. Public configuration and server secrets must be treated differently, and required configuration should be validated at startup.
Learning path
Theory → Example → Code → Practice → Quiz → Challenge → Completion
Step 1
Theory
Configuration includes URLs, feature flags, timeouts and credentials. Public configuration and server secrets must be treated differently, and required configuration should be validated at startup.
Step 2
Example
A browser analytics ID may be public while a payment provider key stays server-only. Missing production secrets should fail startup rather than create partial behavior.
Step 3
Code
typescript
const required = ["DATABASE_URL", "PAYMENT_SECRET"];
for (const key of required) {
if (!process.env[key]) throw new Error(Missing ${key});
}
Step 4
Practice
Review your current application and apply Configuration, Environments & Secrets. Document the current behavior, one production risk, the change you would make, and how you would verify it.
Step 5
Quiz
1. What is the central production concern in "Configuration, Environments & Secrets"?
Step 6
Challenge
Design a production-ready implementation for Configuration, Environments & Secrets. Include failure handling, security considerations, observability, testing and a rollback or recovery path where applicable.
Complete every stage
Work through every step in order, then the lesson will be marked complete.
Each chapter and subtopic has its own public URL under /full-stack-to-production.