How to solve the data inconsistency problem when processing an order through multiple microservices?

Data inconsistency issues when processing orders through multiple microservices are usually addressed using patterns for managing distributed transactions and data consistency. The main approaches:

• Sagas — break down the business process into a series of local transactions in each microservice with compensating actions in case of errors. This ensures eventual consistency without global locks.

• Idempotency of operations — so that repeated calls do not lead to errors or duplication.

• Use of message queues and event-driven architecture — microservices exchange events, which helps synchronize state.

• Two-phase commit transactions (2PC) — rarely used due to complexity and reduced performance.

Example of a saga:

1. The order service creates an order and publishes an "OrderCreated" event.
2. The payment service processes the payment, and if successful — publishes "PaymentConfirmed".
3. The warehouse service reserves the product; if unsuccessful — publishes "StockReservationFailed" and initiates compensation (cancelling payment and order).

Thus, the system achieves consistency without global transactions.