How to protect a payment API from double charges using idempotency

In distributed systems, the issue of double charging during payments is a common scenario caused by network failures and uncertainty in receiving server responses. When a client does not receive confirmation of an operation, retrying the request can lead to duplicate charges. This article on Habr explores methods to prevent such errors through the implementation of idempotency. The author explains the principles of designing idempotency keys, which allow the server to recognize repeated requests and process them correctly without duplicating transactions. The guide also covers strategies for preventing race conditions during parallel data processing and building a fault-tolerant architecture. This resource is essential for payment system developers aiming to ensure data integrity and the reliability of financial operations in unstable network environments.