Number pools — Finn docs

What a number pool is

A number pool is the set of phone numbers an outbound deployment calls from. You pick the numbers when you deploy. There is no separate pool object and no pools screen: the pool belongs to the deployment and ends with it.

You need more than one number because each number carries at most 5 concurrent calls in a deployment. The more numbers in the pool, the more calls the deployment can run at once.

Choose the numbers

In the dashboard:

Open Deploy on a Finn and set the call type to Outbound.
Select the phone numbers to call from. Each must be in Settings → Phone numbers, not used by another live outbound deployment, and not isolated.
Set Max parallel calls. The list runs from 1 to 5 × the number of selected numbers. The default is 2 × the number of selected numbers.
Pick the audience and deploy.

Through the API, an outbound deployment uses one number and up to 5 parallel calls. See api-deployments.

The limits

Rule	Value
Max parallel calls per number	5
Max parallel calls per deployment	5 × numbers in the pool
Carriers per pool	One. The dashboard won't let you mix numbers from different carriers.
Numbers shared between live outbound deployments	Not allowed. A number in one running deployment can't be picked for another.

Your plan's concurrency applies on top of the pool. See concurrency.

Size the pool

Work back from how many calls you want running at once:

numbers needed = max parallel calls ÷ 5, rounded up

For 40 calls at once, you need at least 8 numbers.

That is the minimum. Fewer calls per number spreads volume, and a number that places many calls in a short time is more likely to be labeled as spam by carriers. See spam-labeling.

Keep the pool healthy

Check Health first. In Settings → Phone numbers, look at each number's Health band before you deploy. Leave At risk numbers out.
Isolate weak numbers. An isolated number can't be picked for a new deployment until you release it. A paused number can still be picked, with a warning. To take a number out of a deployment that is already running, stop that deployment.
Rotate a burned number. Rotate number in a number's health drawer rents a replacement and releases the old number once the new one is live.
Match capability to the job. Every number in the pool needs outbound voice. See number-capabilities.

What goes wrong

Symptom	Cause
A number can't be selected when you deploy	It is used by another live outbound deployment, or it is isolated.
A number is greyed out	It is on a different carrier from the numbers already selected.
Max parallel calls won't go higher	It is capped at 5 per selected number. Add numbers.
Answer rates fall across the pool	The numbers are being labeled. Check Health and see spam-labeling.