What is Dynamic Number Insertion, How it Works, and How It Can Help You Accurately Track Phone Calls

What Is Dynamic Number Insertion (DNI)?

Dynamic Number Insertion (DNI) is a short script of code added in your website which is responsible for the dynamic number swapping in order to assign unique phone numbers to website visitors and gathers all the essential data for monitoring a caller’s interactions and journey before, during, and after the phone call.

When a visitor lands on your website, a tracking number is assigned to them from a pool of available tracking numbers. As a result, every individual browsing your site perceives a distinct phone number throughout their visit. Once they leave your website, the phone number is released, ready to be assigned to your next visitor.

DNI ensures that each visitor sees a specific phone number that is tied to their session, allowing you to accurately attribute incoming calls to their respective marketing sources, campaigns, ads, keywords etc.

How does Dynamic Number Insertion actually work?

At its core, Dynamic Number Insertion follows a few simple steps:

1. A visitor lands on your website carrying source data: UTM parameters, a Google Ads GCLID, an organic referrer, or a direct visit.
2. The DNI JavaScript snippet fires on page load and asks the call tracking software: “Which tracking number should this visitor see?”
3. The platform returns a unique phone number from your number pool, mapped to that visitor’s source, campaign, or keyword.
4. The script swaps the default number on the page — in the header, footer, click-to-call buttons, and body copy — with the tracking number, all before the page paints.

When the visitor calls that number, the platform forwards the call to your real business line and logs the call against the original traffic source. The result: complete, keyword-level attribution for every phone conversion.

Number Pool vs. Session-Based DNI

There are two common DNI models, and choosing the right one depends on your traffic volume.

Session-based DNI assigns a unique number to every active visitor session. It delivers the most granular attribution — down to the individual keyword or ad, but requires a larger pool of tracking numbers. Best for PPC-heavy advertisers running Google Ads or Microsoft Ads.

Source-based DNI assigns one number per traffic source (one for Google organic, one for Facebook, one for email, etc.). It uses fewer numbers and is easier to set up, but you only see channel-level attribution, not keyword-level. Best for lower-traffic sites or top-of-funnel reporting.

What gets captured

• Source (PPC, Organic, Referrals, Google My Business, Facebook etc.)
• Keywords (for all PPC)
• The Landing page which drove the call
• The Landing Page, in which the caller landed
• Referring domain
• Medium
• Which tracking number was called
• Date and time of the call
• Caller ID
• Caller’s Location (Country, State, City)
• Call Duration
• Complete page view history of the caller
• UTMs or other custom url parameter
• GCLID

Why marketers swear by DNI (5 real benefits)

Dynamic Number Insertion offers a plethora of benefits that revolutionize call tracking and elevate your marketing endeavors:

For marketers running multi-channel campaigns, the biggest blind spot has always been the phone call. You can track clicks, form fills, and add-to-carts down to the keyword — but the moment someone picks up the phone, the data trail used to go dark. Dynamic Number Insertion is what closes that gap. Here’s why marketing teams across PPC, SEO, and agency ops have made DNI a non-negotiable part of their stack.

1. Real attribution for phone conversions

Without DNI, every inbound call is essentially anonymous traffic. You know the phone rang, but you just don’t know which campaign, keyword, or landing page actually drove it. DNI fixes that by assigning a unique tracking number to every visitor session, so when a call comes in, it’s already tagged with the traffic source, UTM parameters, GCLID, and referring page. The result: phone calls finally show up in your reports as the conversions they really are attributed, scored, and ready to optimize. (See how Nimbata’s call tracking platform handles attribution end to end.)

2. Smarter Google Ads bids around call quality

Most PPC teams optimize Google Ads based on form submissions, because that’s what they can measure. But if half your leads come in by phone, you’re bidding with one eye closed. With DNI feeding call data back into Google Ads, you can bid on the keywords and campaigns that produce qualified calls, not just any calls. Layer in call duration, recording tags, and lead scoring, and you’re optimizing on real revenue signals instead of vanity metrics. Here’s how to track calls back to specific Google Ads keywords using Nimbata.

3. Connecting offline revenue to online campaigns

Phone calls don’t end on your website. They end in a sales conversation, a booked appointment, or a closed deal and most of that revenue lives in your CRM, not your ad platform. DNI is the bridge that ties offline outcomes back to the online ad spend that started them. By passing the tracking data through to your CRM, you can attribute actual revenue, not just lead count, back to the channel and campaign that drove it. Nimbata’s CRM and ad platform integrations push every call event, with its full source data, straight into HubSpot, Salesforce, Google Ads, and dozens more.

4. Powering call analytics, recording, and AI insights

DNI isn’t just an attribution tool, it’s the data layer that makes everything else in modern call tracking possible. Once every call is tagged with its true source, you can layer on call recording to review conversations, call analytics to spot trends across thousands of calls, and AI-powered conversation intelligence to automatically score leads, flag buying intent, and surface common objections. Without DNI, none of that data is tied to a campaign. With it, every conversation becomes a labeled, searchable, optimize-able marketing asset.

Static vs. Dynamic Call Tracking: What’s the Difference?

Unlike traditional call tracking methods that rely on static numbers and incomplete data, Dynamic Call Tracking introduces a paradigm shift:

14+1 questions only DNI can answer

Nimbata’s Call Tracking Solution utilizes DNI to deliver accurate call attribution and gather extensive information from visitor’s browsing behavior and phone call conversations, which later help marketers optimize their campaigns based what actually work, prove their value to their clients, improve their strategies, conversion rates, ad spent, and ROAS. Nimbata helps Marketers answer the following questions:

1. Which Marketing Channels are Driving Calls?
   Marketers can determine which specific marketing channels, such as online ads, SEO, social media, or email campaigns, are driving the most phone calls. This insight helps allocate resources effectively to the most impactful channels.
2. What Keywords or Ad Variations Trigger Calls?
   Call tracking allows marketers to identify which keywords or ad variations are prompting phone calls. This helps refine keyword targeting and optimize ad campaigns for better results.
3. Are Calls Resulting from Mobile or Desktop Visitors?
   Marketers can distinguish whether the majority of calls are coming from mobile or desktop visitors. This information aids in tailoring mobile and desktop experiences to better serve user needs.
4. When Do Calls Occur Most Frequently?
   Call tracking reveals the time of day, day of the week, and specific periods when calls are most common. This data assists in scheduling ad campaigns, optimizing staffing for call centers, and delivering timely customer support.
5. Which Pages and Content Lead to Calls?
   Marketers can identify the pages and specific content that users engage with before making a call. This helps optimize website content and user journeys to encourage more conversions.
6. How Effective are Different Click-to-call CTA Placements?
   Call tracking allow you to add custom parameters so that you can track every minor detail of your phone calls. In this case you can add parameters to your different click-to-call ctas to see what works better for you (e.g. cta on header, in the middle of the page or footer) This knowledge guides cta placement decisions for maximum impact.
7. Are Calls Converting into Sales?
   Call tracking can reveal whether calls generated from specific marketing efforts are translating into valuable outcomes such as sales, appointments, or other conversions.
8. What is the Quality of Phone Leads?
   Advanced call tracking tools can analyze call recordings to determine call quality, helping marketers understand if calls are leading to meaningful interactions and conversions.
9. Which Marketing Touchpoints Influence Callers?
   Marketers can assess which combination of touchpoints across different channels lead to the most calls. This holistic understanding informs multi-channel marketing strategies.
10. What’s the ROI of Marketing Campaigns?
    By correlating call data with sales data, marketers can calculate the return on investment (ROI) of various marketing campaigns and efforts.
11. How Can Call Handling be Improved?
    Call tracking data provides insights into call duration, call routing, and the quality of conversations. Marketers can identify areas for improvement in call handling and training.
12. Are Callers New or Returning Customers?
    Call tracking enables marketers to distinguish between new callers and those who have interacted with the business before. This insight helps tailor marketing strategies to cater to both types of customers.
13. How Many Calls Does it Take to Close a Sale?
    Call tracking data can reveal the average number of calls it takes for a lead to convert into a sale. This information assists in understanding the typical customer journey and refining strategies to shorten the sales cycle.
14. How Many Touchpoints Lead to a Sale?
    Marketers can determine the number of touchpoints across different channels (such as website visits, emails, and ads) that a potential customer interacts with before making a purchase. This insight guides the design of effective multi-touchpoint campaigns.
15. Which Actions/Campaigns Generate the Highest-Value Leads?
    Call tracking enables marketers to discern not only which actions or campaigns are generating the most leads, but also which ones are yielding the highest-value leads. This distinction is crucial in prioritizing efforts towards strategies that result in leads more likely to convert into valuable outcomes, such as sales or long-term customer relationships.

How to set up DNI via nimbata

To add DNI to your website you can also use our wordpress plugin. Check out this step-by-step guide on how to do it correctly.

So, Is DNI right for you?

If we assume that Call Tracking is an ecosystem, then DNI is this little thing that makes the whole ecosystem functional. Not only allows you to track your callers in detail but also helps you deeply understand who your customer is and how interacts with your business.

DNI Questions, Answered