---
title: "Visitor Identification"
slug: "session-and-visitor-handling"
updated: 2025-10-17T12:50:28Z
published: 2025-10-17T12:50:28Z
canonical: "docs.mapp.com/session-and-visitor-handling"
---

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

# Visitor Identification

Mapp Intelligence identifies each visitor through a unique **everID (eid)**, which links all incoming **requests** to the same user across sessions and devices. This identifier must remain constant in every tracking request to ensure consistent analysis and visitor attribution. If no everID is transmitted, Mapp Intelligence applies a simplified identification method based on the **IP address** and **user agent**.

This fallback provides only approximate recognition and should be avoided whenever possible.

Sessions are handled automatically on Mapp’s side, based on the **everID** and the **timestamps** of incoming requests. No explicit session parameter or configuration is required.

---

## First-Party Cookies

With first-party cookies, the everID is generated on the client side and stored in your own domain under the cookie `wt3_eid`. This information is then sent with each tracking request in the parameter `eid`.

| **Property** | **Value** |
| --- | --- |
| **Cookie name** | wt3_eid |
| **Cookie content** | `;[track ID] |
| **Example content** | `;111111111111111 |
| **Cookie path** | / |
| **Cookie lifetime** | 6 months |

### Example Requests

**First call (new visitor)**

```bash
https://track.webtrekk.net/111111111111111/wt?p=600,home&eid=2138210064900146323&one=1
```

**Subsequent calls (returning visitor)**

```bash
https://track.webtrekk.net/111111111111111/wt?p=600,content&eid=2138210064900146323
```

### Optional Parameters

| **Parameter** | **Description** |
| --- | --- |
| **one** | Indicates a new visitor. Use 1 for the first request; for all later requests, use 0 or omit the parameter. |
| **ceid** | *Custom everID.* Use this if you maintain your own persistent user identifier instead of the Mapp everID. |

**Example using a custom ID**

```bash
https://track.webtrekk.net/111111111111111/wt?p=600,home&ceid=XYZ-232-ABC&one=1
```

---

## Third-Party Cookies

If first-party cookies cannot be used, Mapp Intelligence can store the everID as a **third-party cookie** on the tracking domain under **wteid_[track ID]**.

| **Property** | **Value** |
| --- | --- |
| **Cookie name** | wteid_[track ID] |
| **Cookie content** | [ever ID] |
| **Example content** | 4138210064900146323 |
| **Cookie domain** | [track domain] |
| **Cookie path** | /[track ID]/ |
| **Cookie lifetime** | 6 months |

### Example Request

```bash
https://track.webtrekk.net/111111111111111/wt?p=600,home
```

---

## Passing the everID

When using server-to-server tracking, you must explicitly pass a persistent visitor identifier in each request. You can either reuse the everID from the client-side cookie or use your own ID via the ceid parameter.

```bash
https://track.webtrekk.net/111111111111111/wt?p=600,checkout&eid=2138210064900146323
# or, using a custom ID:
https://track.webtrekk.net/111111111111111/wt?p=600,checkout&ceid=CUST-ID-12345
```

> [!NOTE]
> Note
> 
> If both eid and ceid are present, Mapp Intelligence uses ceid for visitor recognition.

---

## Fallback Identification

If neither eid nor ceid is available, Mapp Intelligence attempts to identify visitors based on **IP address** and **user agent**.

This ensures that requests are still processed, but returning visitors may not be correctly linked across sessions.

---

## Best Practices

- Always send the same **everID (eid)** for the same user across all requests and systems.
- Prefer **first-party cookies** for stable, privacy-compliant tracking.
- Use **third-party cookies** only if first-party cookies cannot be set in your domain.
- Send one=1 only for the **first request** of a new visitor.
- Use **ceid** only if your organization manages its own persistent user IDs.
- Avoid sending multiple identifiers for the same visitor.
- For hybrid setups (pixel + S2S), use the **same everID** in both environments.