Workflow Orchestration

If you have a complex process (e.g., User Signs Up -> Send Email -> Create DB Record -> Generate Coupon), don't write one giant function. Use Step Functions (AWS) or Logic Apps (Azure) to orchestrate multiple tiny functions.

1. State Machines

Orchestrators act as **State Machines**. They track exactly where a user is in a long-running process (even if it takes days). They handle **Retries**, **Error Branching**, and **Parallel Processing** visually.

2. Visual Debugging

You can see a flowchart of your logic. If the "Send Email" step fails, you can see it glowing red in the dashboard, see the exact error, and manually re-run that one step without restarting the whole process.

4. Interview Mastery

Q: "Why use an Orchestrator instead of just calling one Lambda from another?"

Architect Answer: "Chaining Lambdas is a **Bad Practice**. It creates tight coupling and you pay twice—once for the caller and once for the callee. If the second function fails, the first one might time out. **Step Functions** are built to handle state and retries natively. They provide a 'Durable' workflow that is much more resilient and easier to debug than nested code calls."