# Cookie management

## Tracking cookie :cookie:

The [JavaScript SDK](/en/setup-guide.md) creates a unique first-party cookie, which is used to measure the performance of advertising campaigns.

With each call to the **Veasybl** platform, the collected information (from the first-party cookie and the browsing context) is used to deliver relevant ads, while preserving the user experience.

In server-side implementations, the retailer’s site can allow **Veasybl** to access the browser's tracking cookie by acting as a cookie proxy.

When the user’s browser requests a page from the retailer's site, the retailer’s server reads the cookie value and then passes it to **Veasybl** via the [API](/en/api-integration/reference.md).

{% hint style="info" %}
The first-party cookie created by the JavaScript library is named **\_vzbl\_uid**.

The lifetime of this cookie is configurable, ranging from 30 days to 12 months, depending on the retailer's preferences.
{% endhint %}

> **First-party cookies** are created by the host domain – the domain the user is visiting. These types of cookies are generally considered good; they help provide a better user experience and keep the session open. This basically means the browser is able to remember key pieces of information, such as which items you add to shopping carts, your username and passwords, and language preferences.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.veasybl.io/en/integration/cookie-management.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.