How to set dynamic DNIS using Set Participant Data before transfer

Architect & Flows
1

We need to set the outbound caller ID dynamically in an Architect flow before transferring to an external number.

Different customers should see different caller IDs based on which product line they are calling about. The Set Participant Data action seems like the right approach, but I can’t get it to work.

2

Set the Outbound Caller Id Number participant attribute before the Transfer action.

Set Participant Data("Outbound Caller Id Number", "+18005551234")
Set Participant Data("Outbound Caller Id Name", "Acme Support")
Transfer to Number("+14155559876")

The trunk must have its caller ID source set to ‘Use Participant Data’. Check Telephony > Trunks > your trunk > Outbound tab.

3

We track which dynamic DNIS produces the highest answer rates.

# Analyze answer rate by outbound caller ID
body = {'interval': interval, 'groupBy': ['outboundCallerIdNumber'],
        'metrics': ['nConnected', 'nOffered']}
result = api.post_analytics_conversations_aggregates_query(body)
for row in result.results:
    dnis = row.group.get('outboundCallerIdNumber', 'Unknown')
    rate = row.data[0].metrics[0].count / row.data[0].metrics[1].count * 100
    print(f'{dnis}: {rate:.1f}% answer rate')
4

From a project management perspective, test every DNIS combination before go-live.

We had 8 product lines × 3 regions = 24 unique caller ID combinations. Each one needed to be tested end-to-end: set participant data → transfer → verify the caller ID displays correctly on the receiving phone. Budget 2 full days for DNIS validation.

5

Under TCPA, the caller ID must be a valid number owned by your organization.

Spoofing a caller ID that doesn’t belong to you is a federal violation. Ensure every DID used as a dynamic caller ID is provisioned in your carrier account and routes back to your organization when called.