Idempotency in Data Pipelines: How to Prevent Duplicate Records

A pipeline that runs twice should produce the same result as one that runs once. That property is idempotency, and its absence is one of the most common sources of silent data corruption in integration systems. A partially completed run gets retried, the retry reprocesses records that already loaded, and the destination ends up with duplicates that neither the source system nor any monitoring alert ever surfaced. Designing for idempotency is not complex, but it requires making explicit decisions