How to use the caller ID prefix filter for geo-routing

Available on Marketing and Agency plans only.

The Caller ID Prefix filter reads the first digits of an incoming caller's number (country code or area code)

Then, it routes the call to the destination you assign to that prefix.

This powers Geo-routing: the ability to send callers to a local office, regional team, or franchise branch based purely on where they're calling from.

Common use cases include:

Routing Chicago-area calls (312) to a Midwest sales team.
Sending UK callers (+44) to an international support line.
Blocking entire country codes from reaching your numbers at all.

How Geo-routing with Caller ID Prefix works

When a call arrives, Nimbata checks the caller's number against the prefixes you've configured. If there's a match, the call follows the path you defined for that prefix. Any number that doesn't match a configured prefix follows the default "remaining" path — which you also define.

You can configure as many prefix routes as you need. Prefixes can also be used to route anonymous calls, send certain regions straight to voicemail, or hang up immediately.

Step 1. Open the Call Flow Builder

Go to Tracking > Call Flows.
Click + Add to create a new call flow.

Step 2. Add the Caller ID Prefix filter

Click the + button on the canvas.
Select Caller ID Prefix from the Filters menu.

Step 3. Enter the prefixes you want to isolate and define what happens to them

Type the country codes or area codes you want to handle differently into the prefix field.
Click the + below that branch and select the routing action for those callers (e.g. Hang Up, Voicemail, or Dial to a specific destination).

Step 4. Define what happens to all other callers

Click the + button on the remaining-callers branch.
Select the routing action for everyone who doesn't match a defined prefix.

Step 5. Add additional prefix routes as needed

Repeat Steps 3-4 for each additional region or country you want to handle differently.
Connect each new prefix branch to its appropriate routing action.

🎉 Your Geo-routing call flow is set up. Assign it to tracking numbers under Tracking > Numbers to go live.

Detailed Guide: How to block calls from specific countries

Detailed Guide: How do I handle anonymous calls without losing any leads?

Detailed Guide: How to assign tracking numbers to call flows

Updated on: 01/04/2026

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