Overview
Channel selection hierarchy is how CX Platform decides which channel to use when delivering a communication, and what to do if that channel can't reach the recipient. Rather than relying on a single channel and hoping it lands, you can set up a fallback chain — try email first, drop to SMS if it bounces or there's no email address on file, then fall back to print as a last resort.
It's also where you set up parallel sending — pushing the same message out across multiple channels at the same time — and stagger the timing so channels don't all land at once.
You'll find these settings on the Channel selection tab inside any Application. This guide is a tour of what's possible. For a step-by-step on configuring it for your own Application, see Configure failed delivery contingency.
Heads up
The settings on this tab apply to realtime API notifications only. Batch jobs and scheduled sends aren't affected by what you configure here.
Three priority levels
Each Application supports up to three priority levels — Priority 1, Priority 2, and Priority 3. CX Platform tries Priority 1 first. If the record bounces or doesn't have the contact info needed (for example, no email address on file), it routes to Priority 2, and then Priority 3 as a final fallback.
That gives you a sensible fallback chain without writing a single line of code. A common setup is email at Priority 1, SMS at Priority 2, and print at Priority 3, so wherever the recipient is reachable, the message gets there.
One channel or several at once
For each priority, you can choose a single channel — Email, SMS, or Print — or pick Multiple if you want more than one channel firing at the same priority level.
The Multiple option is what unlocks parallel sending. When it's selected, you get fine-grained control over each channel within that priority — enabling each one independently, marking it as required, controlling whether a bounce escalates, and setting a per-channel delay.
So if you want both an email and an SMS to go out at Priority 1, you'd select Multiple and enable both within it.
The Required flag
Marking a channel as Required adds a guardrail. The priority will only fire if the record has the contact info needed for that channel.
For example, if Priority 1 is set to Email + SMS with both marked Required, but the record doesn't have an email address, the platform skips Priority 1 entirely and moves to Priority 2. It won't just send the SMS on its own. Handy when you want certainty that a recipient gets the message through both channels, or not at all.
Bounce escalation
The Send next priority if bounced checkbox controls whether a bounce on a channel cascades to the next priority. Tick it, and a bounced send routes the message to the next priority. Leave it unticked, and the chain stops there.
This gives you per-channel control over how aggressively the platform chases a delivery. A common pattern: if email bounces, you want a print fallback, so you'd tick the box on email. But if the SMS bounces, you don't need a print record on top of everything else, so you'd leave it unticked and let the SMS fail quietly.
Quick tip
When you've selected Multiple for a priority, each channel gets its own Send next priority if bounced control. That's how you can cascade on email but not on SMS within the same priority group.
Per-channel delays
When you're sending across multiple channels at once, you can stagger the timing by setting a delay (in minutes) on any channel. Useful when you want one channel to arrive ahead of the others.
A typical example: sending an email and an SMS together, but holding the SMS back by 5 minutes so the email lands first. The SMS then arrives as a gentle follow-up rather than landing at the same time.
The capabilities at a glance
Channel selection hierarchy gives you four building blocks working together:
- Priority order — a fallback chain across up to three levels.
- Multiple channels — parallel sending within a single priority.
- Required and bounce controls — per-channel rules for when a priority fires and whether a bounce cascades.
- Delay — timing control so channels arrive in the order you want.
Together they let you shape delivery logic to match how recipients should actually be reached, with sensible fallbacks, the right level of redundancy, and timing that feels considered rather than chaotic.
What's next
Now that you've got a feel for what's possible, head to Configure failed delivery contingency for a step-by-step on setting up priorities, channels, required flags, bounce escalation, and delays for your own Application.