# Adding the Customer information

On every page, the customer information *should* be tagged if the customer is logged in. If the customer isn't logged in, this but can be omitted.

The customer information is primarily used for sending personalized triggered emails and for building multi-channel experiences.

```js
nostojs(api => {
  api.setTaggingProvider("customer", {
    email: "john.doe@example.com",
    first_name: "John",
    last_name: "Doe",
    customer_reference: "e18daf14-d715-4d77-82f2-93eceb4ae1ef",
    type: "loggedin",
    newsletter: false
  })
})
```

{% hint style="info" %}
To learn more about the `api.setTaggingProvider` usage, please refer to the [official API documentation](https://nosto.github.io/nosto-js/interfaces/client.API.html#settaggingprovider).
{% endhint %}

The full schema for customer tagging is defined [here](https://nosto.github.io/nosto-js/interfaces/client.PushedCustomer.html)

or via DOM tagging

```markup
<div class="nosto_customer" style="display:none" translate="no">
  <span class="email">john.doe@example.com</span>
  <span class="first_name">John</span>
  <span class="last_name">Doe</span>
  <span class="customer_reference">e18daf14-d715-4d77-82f2-93eceb4ae1ef</span>
  <span class="marketing_permission">false</span>
</div>
```

## Tagging marketing permission

The new marketing-permission flag denotes whether the customer has consented to email marketing. If the marketing-permission field is omitted, we assume that the current customer has not given their consent and Nosto will refrain from sending out any personalized triggered emails.

The marketing permission is false by default but if a user has explicitly agreed to receive marketing then you can set it to true manually. In practice, this means reading and mapping the value from opt-in for marketing in your platform e.g. a consumer explicitly subscribed for marketing emails when checking out.

The marketing-permission should be included as a part of the customer tagging and should be rendered on all pages.

## Tagging customer reference

The customer-reference can be leveraged to unify sessions across channels such as between online and offline. It is a unique identifier provided by you that is used in conjunction with the Nosto cookie. The customer-reference can also be used to uniquely identify users in lieu of an email address.

The customer-reference should be a long, secure and a non-guessable identifier. For example, use your internal customer-id or the customer's loyalty program identifier and use a secure hash function like an HMAC-SHA256 to hash it.


---

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