We’re architecting a new integration to sync opportunities between Salesforce Winter '25 and our enterprise ERP system. The debate in our team is whether to use REST or SOAP API for this critical data flow. We handle approximately 5,000 opportunity updates daily with complex line item structures.
From what I understand, REST is more modern and lightweight, but SOAP offers better error handling and transaction support. Our key concerns are:
- Reliability during network interruptions - we can’t afford to lose opportunity data
- Error handling capabilities - need detailed error messages for debugging
- Payload size limits - some opportunities have 50+ line items with attachments
I’ve seen arguments for both approaches. REST seems popular for its simplicity and JSON format, while SOAP provides built-in retry mechanisms and formal contracts via WSDL. What are your experiences with large-scale opportunity synchronization? Which protocol has proven more reliable in production environments?
We migrated from SOAP to REST last year for opportunity sync and haven’t looked back. REST with proper error handling middleware gives you everything SOAP does but with much better performance. The JSON payload is 30-40% smaller than XML for the same data. For reliability, implement exponential backoff retry logic on your side - don’t rely on the API protocol to handle it.
From a reliability standpoint during network interruptions, neither protocol inherently handles this better - it’s about your implementation. Both REST and SOAP will fail if the network drops mid-request. The difference is in recovery. SOAP’s stateful nature can maintain transaction context, but Salesforce’s APIs are stateless regardless. Implement idempotency keys with REST to prevent duplicate records on retry. Use external IDs to make your sync operations upsert-based rather than create-based.
I’d argue SOAP is still superior for enterprise integrations despite being older. The WSDL contract ensures both systems agree on data structure, which prevents runtime errors. SOAP’s fault elements provide structured error information that’s easier to parse programmatically. With REST, you’re parsing HTTP status codes and custom error JSON structures. Also, SOAP supports WS-Security for message-level encryption if you’re transmitting sensitive opportunity data.