What Is Dynamic Number Insertion (DNI)?

Dynamic number insertion (DNI) is a technique that swaps the phone number shown on your website for a tracking number, based on how each visitor arrived. A visitor from a paid ad sees one number, an organic visitor sees another. When they call, the call is credited to the source behind it.

Last updated: November 8, 2026

How DNI works, step by step

Here is what happens for a single visitor on a website that uses DNI.

1 A visitor arrives from a channel: a search ad, an organic result, a social post or a link on another site.
2 A small script reads how they arrived, using information such as the referring page and the campaign parameters in the link.
3 The script picks a number from a pool that belongs to that traffic source, and swaps it into the page wherever your phone number appears.
4 The same number stays with that visitor while they browse, so the number they see is the number they call.
5 They call it. The call is forwarded to your real line or call flow.
6 The call is matched to the visit, so the platform knows the source and campaign, and logs it with duration and outcome.

How DNI swaps numbers by traffic source

The idea is simple: each traffic source owns a set of numbers. The script decides which set to use, then shows one number from it.

Paid search visitor → a number from the Google Ads pool.
Organic search visitor → a number from the organic pool.
Social visitor → a number from the social pool.
Direct or unknown visitor → your default number, or a number from a direct pool.

Why DNI needs a number pool

A single tracking number can only be told apart from other callers while few people see it at once. If many visitors from the same source are on the site at the same moment, a pool of several numbers lets the platform give each active visitor a different one, so each call can still be matched to a visit. In CallRing AI, bulk numbers attach to a DNI pool so they can rotate across your website visitors.

An example

A law firm has one phone number in its website header. With DNI, a visitor who clicked a Google ad sees a number from the Google Ads pool, while a visitor who found the site through a blog post sees a number from the organic pool.

Both numbers ring the same front desk. At the end of the month, the call log splits the calls by source, even though the firm only has one website and one slot for a phone number.

Why DNI matters for marketers

Static numbers are fine for one flyer. Websites are different: one page receives traffic from many channels at once. DNI is what lets one page report on all of them.

Per-channel call data for paid search, organic, social and referral traffic on the same site.
Better conversion tracking. Calls can be sent to Google Analytics 4 and used as conversions. See how to track phone calls in GA4.
Cleaner paid-search reporting. See the calls behind your ad spend. Read how to track phone calls from Google Ads.

Things to know before using DNI

DNI needs a script on your website, so your site must allow it. It also changes the number visitors see, so keep your main number on directory listings and use DNI numbers only on your website, and check each directory’s guidance. In CallRing AI, dynamic number insertion is available on the Starter plan and above.

Frequently asked questions