> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gocertify.me/llms.txt
> Use this file to discover all available pages before exploring further.

# Shopper Insights

> Using Tracking Links to Gather Shopper Insights.

### Post Verification Tracking

Once a shopper has completed a verification flow they will be redirected to a custom link, known as a *tracking link*. Beyond simply redirecting shopper's to a specific page on your website post-verification,
you can customise this tracking link to pass real-time information about the [user group](/section/buildRewardFlows/closedUserGroups) of that shopper. You can set tracking links up at a brand level or make them unique per campaign.

<Tip>
  If you are using an affiliate network this is also the link you will use to track conversions (see [Affiliate Tracking](/section/trackImpact/affiliateTracking)).
</Tip>

#### Passing verification type

To gain real-time insights into your shoppers you can use this tracking link to pass a special query parameter with the details of the campaign or group a shopper was verified with.

For example, if you are running campaigns for Students, you can store this information in the URL as a query parameter:

```
https://example.com/your-page?campaign=student
```

You can give this parameter any name you want, including as an UTM parameter (i.e. `utm_campaign`). If you push this data to your datalayer you can then use it in real time to segment your shoppers and unlock further personalisation.

#### Passing Custom Parameters

In addition to receiving information about verifications, you can also pass your own data through the verification process
and receive it back at the end. This bidirectional data flow is particularly useful for referral campaigns or when you need to maintain session continuity.

To do this, we support 2 special parameters, called `subid` and `clickref`. The only difference between the two is
that `subid` is persisted to our verification database, while `clickref` is ephemeral and will only be available in the
current session.

See how to set them in your landing pages [here](/section/gettingStarted/landingPages). To gain insights into which of these shoppers are converting, implement [transaction tracking](/section/trackImpact/transactionTracking)