How systems are made to talk to each other: API design, CRM–ERP synchronisation, webshop connectors and the failure modes to design around.
Integration work is where a business finds out what its data actually looks like. Two systems that both call something a customer will disagree about it — different keys, different addresses, one that permits duplicates and one that does not. Most of the effort in an integration project is that reconciliation, not the connection.
The patterns below come from connecting webshops to accounting systems, CRMs to ERPs, and production floors to reporting. They cover the parts that decide whether an integration survives its second year: idempotency, retry and backoff, what to do with a record that fails validation at three in the morning, and how to make a sync auditable when someone asks why a figure changed.
Where a documented connector already exists, using it beats building one. The articles are explicit about when that is true and when the connector's limits make it the more expensive option.
