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

# Visitor footprint timestamps

> Visitor footprint timestamps represent two significant events for a browser or device:

* The first time a browser or device appeared in your application.
* The most recent identification before the current event.

These timestamps when combined with Smart Signals (e.g. [IP Geolocation](/docs/smart-signals-reference#ip-geolocation), etc) can be valuable in detecting account takeover and other fraud.

## Availability

Visitor footprint timestamps are available for all plans at no additional cost. These fields are included in:

* [Server API v4 event responses](/reference/server-api)
* [Webhook v4 payloads](/docs/webhooks)
* [Sealed client results](/docs/sealed-client-results)

## Representation in API response

In API responses, visitor footprint timestamps are represented by the following JSON properties:

1. `identification.first_seen_at`
2. `identification.last_seen_at`

`last_seen_at` contains the previous identification timestamp. For a visitor's first identification, it equals `first_seen_at`.

<CodeGroup>
  ```json JSON theme={"theme":"github-dark-dimmed"}
  {
    // ...
    // Timestamps are Unix millisecond integers
    "identification": {
      "first_seen_at": 1647430261101,
      "last_seen_at": 1648118914023
    },
    // ...
  }
  ```
</CodeGroup>

***

[Identifying users in hybrid app frameworks](/docs/identifying-users-in-hybrid-app-frameworks)

[Changelog (Android SDK)](/docs/changelog-android-sdk)