It can be as long as you have some kind of identity information associated with the request, and provided alongside any requests that are the 'same'. e.g. Inst

It can be as long as you have some kind of identity information associated with the request, and provided alongside any requests that are the 'same'. e.g. Instead of saying "Insert a transaction for £20", you say, "Insert a transaction that entity A calls 1234, for £20". Stripe use something like this to ensure that as long as you call their API to ask for a payment and use the same key, they won't charge the person twice. https://stripe.com/docs/api#idempotent_requests https://stripe.com/docs/api#idempotent_requests