What is a Saga?

A saga is a multi-step transaction with automatic rollback. If any step fails, all previously completed steps are undone via compensation actions.

The Problem

Multi-step operations can fail partway through:

Step 1: Reserve inventory  ✓
Step 2: Charge payment     ✓
Step 3: Ship order         ✗ (fails!)

Result: Payment charged but order not shipped!

The Solution

Sagas automatically undo completed steps:

Step 1: Reserve inventory  ✓
Step 2: Charge payment     ✓
Step 3: Ship order         ✗ (fails!)

Compensation:
  Undo Step 2: Refund payment  ✓
  Undo Step 1: Release inventory  ✓

Result: System back to original state

Key Properties