Omnichannel Messaging Fallback

What Is Omnichannel Messaging Fallback?

It's the layer that decides what happens after a message doesn't deliver the way you expected. Instead of a failed send simply disappearing into a log, a fallback rule you've configured can route it to a different channel - so the outcome of a failed WhatsApp send is a second attempt on SMS, not silence.

The important qualifier is configurable. Fallback behavior depends on the rules you set up for a given message type, the delivery and status signals a channel actually supports, and the channel priority you define - it is not a single automatic behavior applied identically to every message you send.

Why Businesses Need Message Fallback

• Not every customer has a given app installed, or has opted in to receive messages on it.

• Rich channels like RCS depend on device and carrier support that varies across a customer base.

• A single channel having an outage or degraded delivery shouldn't mean every affected message goes unanswered.

• Time-sensitive messages - a login code, a payment alert - can't always wait for a manual check and resend.

Multi-Channel Routing & Business Rules

Routing is configured per use case, not applied as one blanket rule across everything you send. Three inputs shape how a route behaves:

• Delivery-status-based routing - the fallback check looks at the actual delivery status a channel reports back, such as sent, delivered or failed, within the time window you set.

• Channel availability - whether a channel is reachable at all for a given recipient, such as a number not opted into WhatsApp or a device without RCS support.

• Business rules - the channel priority order, wait time before escalating, and whether a given message type falls back at all, all set by you per use case.

A login OTP and a promotional broadcast can be configured very differently: the OTP might escalate within seconds, while the promotional message might not fall back at all, since a channel-blind marketing send to a phone call isn't the outcome most businesses want.

Unified Message Tracking & Analytics

Every message keeps the same ID across a fallback route, regardless of how many channels it moves through before delivery completes. That means your application - and your dashboard - can see the full journey of one message, not three unrelated log entries:

Developer Integration

Fallback is configured as part of the same message request used for a normal send - a channel priority array and a fallback condition, rather than a separate system to integrate:

POST /v1/messages
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

{
  "to": "+919876543210",
  "channel_priority": ["whatsapp", "rcs", "sms"],
  "template": "order_confirmation",
  "params": ["Rohan", "#BL123456"],
  "fallback": {
    "on": "undelivered",
    "wait_seconds": 30
  }
}

Whichever channel completes delivery, the webhook event for that message carries the same message ID and the channel it actually delivered on, so your application can reconcile the request without extra bookkeeping. Full API detail: API Documentation.