Idempotency

Idempotency is the property of an operation where running it multiple times produces the same result as running it once. Essential for Dynamics 365 integrations because distributed systems retry — network timeouts, webhook redeliveries, Service Bus retries all produce duplicate message arrivals. A non-idempotent integration receiving the same event twice creates duplicate records, double-charges customers, sends repeated notifications. Patterns for idempotency: Upsert with alternate key (Dataverse's natural idempotency for record creation), check-before-create (query for existence first; acceptable at low volume), correlation IDs (track processed event IDs and skip duplicates), natural keys (business identifiers that detect duplicates inherently). Design every integration for idempotency; the cost is small, the protection is substantial.