> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.nimbata.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# DNI script 101: what is dynamic number insertion?

| To set up your Dynamic Number Insertion (DNI) script, follow this guide: https://help.nimbata.com/en/article/how-to-install-and-configure-your-dni-script-1vrata9/

### **Defining Dynamic Number Insertion (DNI)**

* Dynamic Number Insertion (DNI) is a JavaScript script you install once on your website. 
* When a visitor lands, Nimbata temporarily assigns a tracking number from your pool to their session. 
* That number replaces your regular business number for as long as they browse. 
* When they leave, the number returns to the pool for the next visitor.
* Nimbata can attribute each call to the exact source, campaign, keyword, and landing page that brought the visitor in.

### DNI vs. source-based tracking

**Source-based tracking** 
* It assigns one fixed tracking number to a channel (e.g. Google Ads). 
* Every visitor from that channel sees the same number, so attribution stops at the channel or campaign level.

**Dynamic Number Insertion** 
* It assigns numbers per session, so attribution can reach down to the keyword, ad variation, and landing page. 
* It's the right choice when you need call data at the same granularity as your click data.

### How many tracking numbers do you need?

Pool size depends on your peak concurrent visitors and average session length. 
Use the [Nimbata number pool calculator](https://www.nimbata.com/features/number-pool-calculator) to get a recommendation.

Detailed Guide: [**How to calculate the size of your tracking number pool**](https://help.nimbata.com/en/article/how-to-calculate-the-size-of-your-tracking-number-pool-k4cca9/)
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🎉 Ready to set it up? Continue with [**DNI script 101: how to install and configure it**](https://help.nimbata.com/en/article/dni-script-101-how-to-install-and-configure-it-1l7zt51/).