Idempotence

Idempotence is a fundamental concept in computer science, particularly in distributed systems and network protocols. It refers to the property of an operation that ensures that repeated attempts to perform the same action will not cause unintended side effects or lead to inconsistent states.

It's not just a theoretical mathematical concept with a difficult-to-pronounce name, it has practical utility in our daily lives. For example, when we receive a bill by mail, we make the payment. If we receive the same bill again, we will not make a second payment. We will find a way to not pay the bill more than once, even if we receive several letters for the same bill.

Idempotence is not only useful in avoiding undesirable effects and improving system reliability but also in cost-saving by avoiding unnecessary requests and reducing complexity. In various layers of a system, from API design to Infrastructure as Code, idempotence is a useful property to have.

When working on any layer or aspect of the architecture, it is important to think about how this property can be applied to improve the system. By understanding and implementing idempotence, we can make our systems more efficient, reliable, and cost-effective.