Definition
A property of an API operation where the result is the same whether you make the call once or multiple times.
Why It Matters
If a user clicks 'Pay' twice, you don't want to charge them twice. Idempotency ensures that the second request is recognized as a duplicate and ignored.
How It Works
- 1
The client sends a unique `Idempotency-Key` header with the request.
- 2
The server checks if it has seen this key before.
- 3
If yes, it returns the cached response.
- 4
If no, it processes the request and saves the key.
The NetForce Take
Mandatory for any financial or mission-critical system we build. We assume networks are unreliable and users will double-click.