Tracking numbers in Nimbata can either live individually or under a group. The latter are collectively known as a 'Swap Group'.

This article explains both and answers some related commonly-asked questions.

The two levels

Swap groups

A swap group is a named collection of tracking numbers that share the same source, call flow, and DNI swap configuration.

The group name is what you see as the heading, e.g. "Austin - Google Ads" or "Phoenix - All Sources".

• The swap group is the unit that the DNI script works with.
• When a visitor arrives from a matching source, the script pulls one number from that group's pool and displays it to the visitor.
• All numbers in the group are interchangeable for this purpose.

Tracking numbers

• The individual numbers listed under each swap group are the actual phone numbers in that pool.
• Each one can be assigned a call individually or receive calls as part of the group's pool rotation.
• If you see two numbers under "Austin" and four under "Phoenix", that means Austin has a pool of two and Phoenix has a pool of four.
• The pool sizes were set based on the expected traffic volume for each location.

Why multiple numbers under one group?

• A single number can only handle one simultaneous call.
• If two visitors from the same source arrive at the same time, each needs their own unique number to maintain accurate session attribution.
• The pool exists to cover concurrent visitors.
• The larger your peak simultaneous traffic, the more numbers you need in the pool.

Detailed Guide: How to calculate the size of your tracking number pool

Detailed Guide: How many tracking numbers do you need?

Do you need different numbers for different departments?

Not necessarily.

The decision depends on whether you want to measure departments separately.

• If your goal is to route calls to different departments and you do not need separate reporting per department, a single call flow with a Keypad Entry (IVR) action can handle the routing. One pool of tracking numbers, one swap group, one call flow; callers press 1 for Sales and 2 for Support.
• If you want separate call volume reporting, separate conversion tracking, or separate workflow rules per department, then a dedicated swap group per department makes sense.

Detailed Guide: How to add a keypad entry (IVR)

Detailed Guide: How to structure tracking numbers for multiple traffic sources

Can you use the same call flow across multiple swap groups?

Yes, you can.

• A call flow can be assigned to multiple swap groups or individual numbers.
• If your clients in Austin and Phoenix have identical routing logic, they can share one call flow.
• Changes to that flow apply everywhere it is assigned.
• If one client needs different routing, create a separate call flow for them.

Detailed Guide: How to set up call flows

Can you duplicate a call flow to use for another client?

Yes. Rather than rebuilding a call flow from scratch for a new client, you can duplicate an existing project (which carries over the call flow structure) or manually recreate the flow using the same actions.

Detailed Guide: How to create a new project, add multiple ones, or duplicate projects

Detailed Guide: How to set up swap groups

Detailed Guide: Tracking numbers 101: how to set up call tracking numbers with Nimbata

Updated on: 05/05/2026