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I think the answer is probably like most things: it depends. - If the external service supports idempotent operations, use that option. - If the external serv

I think the answer is probably like most things: it depends. - If the external service supports idempotent operations, use that option. - If the external service doesn't, but has a "retrieval" feature (i.e. lookup if the thing already exists, e.g fetch refunds on a given payment), use that first. - If the system has neither, assess how critical it is to avoid duplicates.

shineDaPoker 8mo ago
This matches my thinking. The retrieval/lookup approach is exactly what I built - basically Option C with an observe-before-act pattern. For APIs that support idempotency keys (Stripe, etc.), I use those. For ones that don't but have retrieval (most do), I check first before retrying. The question I'm wrestling with: is the extra round-trip for the lookup worth it? Or should I just accept the edge cases where it duplicates? What's your threshold for "critical enough to avoid duplicates"? Payments obviously yes, but what about notifications, reporting, analytics events?