Idempotency

In simple terms, idempotency is the property where an operation can be applied multiple times without changing the result beyond the initial application.

Think of an elevator button: whether you press it once or mash it ten times, the elevator is still only called once to your floor. The first press changed the state; the subsequent ones are “no-ops.”

In technology, this is the “secret sauce” for reliability. If a network glitch occurs and a request is retried, idempotency ensures you don’t end up with duplicate orders, double payments, or corrupted data.

Popular Examples

• The MERGE (Upsert) Operation
• ABS(-5)
• Using Terraform to deploy server