Dynamic Number Insertion (DNI)

1. A visitor lands on the site. The tracking script records the source, campaign, click ID and landing page.
2. The script takes a number from a pool and swaps it into every place the phone number appears, for that visitor's session.
3. The visitor calls the number. The call is forwarded to the real business line; the caller notices nothing.
4. The call is matched to the session that was shown that number, and inherits its source, campaign and keyword.
5. The call becomes a conversion: recorded, attributed, and sent to the ad platforms like a form fill would be.

The pool has to be large enough that two visitors are not shown the same number at the same time. A busy site needs more numbers than a quiet one; the tracker rotates them and frees a number when its session ends.

A visitor who never reaches the website cannot be shown a swapped number. Offline sources get a fixed tracking number each: one on the Google Business Profile, one in the print ad, one on the van, one on the radio spot. A call to that number is attributed to that source, without a session. Both kinds run side by side, so calls from ads, from the profile and from the flyer sit in one report.

• Dynamic: the website

  A number per visitor session, inheriting source, campaign, keyword and pages. For every call that starts with a click.

• Fixed: the offline source

  A number per channel, printed or listed once. For the Business Profile, print, radio, events and vans.

• Source, campaign, ad and keywordThe attribution data of the session that saw the number, down to the search term on Google Ads.
• The click IDWith the gclid or fbclid on the call, a qualified call can go back to Google or Meta as a conversion. See click ID.
• A recording and a summaryCall tracking tools record the call and, increasingly, summarise it, so a booked job and a wrong number are told apart before the count reaches the ad platform.

• Numbers cached by the browser or memorised by a repeat caller can be dialled outside a session, so the match falls back to the last session that saw the number.
• Google Business Profile and directory listings need the fixed number, not the swapped one, or the profile shows a different number than the site.
• A pool that is too small assigns one number to two concurrent visitors, and one of the calls is misattributed.
• Porting the real business number is unnecessary: the tracking numbers forward to it.

Dynamic number insertion turns a phone call into a tracked conversion by swapping the number per visitor and matching the call to the session. Pair it with fixed numbers for offline sources and the phone becomes a channel you can attribute, report and send back to the ad platforms like any other. See phone call leads for the lead gen case.