Modern web applications frequently interact with APIs that perform critical operations such as payments, order creation, or data updates. One common problem developers encounter is duplicate requests caused by: users double-clicking buttons unstable internet connections automatic retries browser refreshes during a request Without safeguards, these duplicates can lead to serious issues like multiple charges, duplicated orders, or inconsistent data . To solve this, many modern APIs rely on a concept called idempotency . What is Idempotency in API Requests? In simple terms, idempotency means that performing the same operation multiple times produces the same result as performing it once . In API design, this means that sending the same request multiple times should not create multiple side effects . This is usually implemented using a unique request identifier called an Idempotency Key .…