Why should you care?

ShopNest cannot lock payment and inventory in one ACID transaction across services.

See it live — copy this example

Sketch the architecture on paper. These lessons focus on concepts and trade-offs.

Orchestrated saga PlaceOrder:
  1 Reserve stock → 2 Capture pay → 3 Confirm order
Compensate: if 2 fails → release stock; if 3 fails → refund + release

State machine stored: PENDING/RESERVED/PAID/CONFIRMED/CANCELLED

Run Example »

This lesson uses terminal or setup steps. Run commands on your computer — the live editor appears on coding lessons.

What happened?

• Each step is locally transactional and idempotent.
• Compensations undo prior work.
• Orchestration is easier to observe; choreography avoids a central boss but can be harder to trace.

Practice next

1. Write ShopNest steps and compensations.
2. Store saga state durably.
3. Make each step idempotent with keys.
4. Add a timeout that auto-cancels PENDING sagas.
5. Emit saga events for tracing.

Remember

Sagas replace distributed ACID. Compensate deliberately. Idempotent steps + visible state.

Checkout orchestrator

ShopNest saga service drives reserve→pay→confirm.

Outcome: Support can see exactly which step failed.