---
title: "Channel fallback"
description: "Channel fallback automatically resends a message over a second channel when the first one cannot deliver it, for example trying WhatsApp, then RCS, then SMS, based on rules such as \"recipient not on the channel\" or \"not delivered within 60 seconds\"."
canonical: "https://omnichannels.ai/glossary/channel-fallback/"
language: "en"
updated: "2026-10-10"
publisher: "BroadNet Technologies"
brand: "OmniChannels.ai"
---

# Channel fallback

Canonical: https://omnichannels.ai/glossary/channel-fallback/
Language: en
Publisher: OmniChannels.ai by BroadNet Technologies

**Definition:** Channel fallback automatically resends a message over a second channel when the first one cannot deliver it, for example trying WhatsApp, then RCS, then SMS, based on rules such as "recipient not on the channel" or "not delivered within 60 seconds".

A fallback chain is defined per use case. The first channel is usually the richest or cheapest for that message; later channels have wider reach. Triggers can be an immediate error (number not on WhatsApp, RCS not supported by the handset), a failed or rejected status, or a timeout without a delivered receipt.

Timeouts should match urgency: a few tens of seconds for OTPs, longer for reminders. Content needs a version for each channel, for example a WhatsApp template with buttons and an SMS text under the segment limit, and links should be tracked per channel so you can see which one converted.

Avoid double messaging: once a later channel is triggered, ignore late delivery receipts from the earlier one, or define clearly which one wins. Also respect each channel's rules; a WhatsApp marketing message needs WhatsApp opt-in, and promotional SMS in markets such as the UAE needs a registered sender and quiet-hour compliance.

Measure delivery and conversion per step to tune the order. In the GCC, WhatsApp is widely used, RCS reach depends on device and operator support, and SMS remains the universal floor.

OmniChannels.ai supports channel fallback, for example WhatsApp, then RCS, then SMS, configured per use case, with delivery statuses normalised into one webhook format.

## Example

```
OTP flow: WhatsApp authentication template → if not delivered in 30 s, SMS → if code not entered in 60 s, offer voice OTP.
```