Event-Driven vs Task-ID Based Integration Between Appian and External Systems

Hi everyone,

We're building a bi-directional integration between Appian (BPM) and an external multi channels systems CRM, Mobile, Kiosk, Corebank etc. We have two architectural approaches and are looking for insights or best practices from the community:

Approach 1: Task-ID Driven

• CRM receives a generated Appian task ID via API

• CRM later calls a second Appian API to complete that specific task by its ID

Approach 2: Event-Driven Integration with Correlation ID (Using Appian Events)

A shared correlationId (UUID) is generated and passed between CRM and BPM.

Appian subprocesses register to Receive Message Events or wait via correlation-aware logic.

CRM communicates by sending events (e.g., KYC_COMPLETED, DOCS_SUBMITTED) using a unified API.

Appian routes events internally using correlationId + eventType.

What I'm Looking For:

Is there an Appian-recommended best practice for choosing between task-based vs event-driven integrations?

Are Receive Message Events and correlationId-based routing commonly used in enterprise Appian implementations?

Any tips for designing a scalable Appian event router that can map CRM responses to the right subprocess?

Thanks in advance — would love to hear from architects or anyone who's built enterprise-scale Appian integrations