Same order, two sales orders

An external system sends order A-1042 and NetSuite creates the sales order. The response never arrives because of a network drop. The system retries… and without protection, a second order is created.

The fix is to make retries safe (idempotency). Use the external system’s identifier as the External ID: NetSuite won’t allow two records of the same type with the same External ID.

// RESTlet (SuiteScript 2.1): look up before creating
const existing = query.runSuiteQL({
  query: 'SELECT id FROM transaction WHERE externalid = ?',
  params: [payload.orderId]
}).asMappedResults()[0];

if (existing) return { id: existing.id, duplicate: true };

const so = record.create({ type: record.Type.SALES_ORDER });
so.setValue({ fieldId: 'externalid', value: payload.orderId });