Cross-Device Visitors

What is CDV (Cross-Device Visitor)

CDV is a logically unified user whose actions have been recorded across multiple devices (desktop, smartphone, tablet, etc.) but recognized as belonging to the same person.

Creating a customer card

Description

A partner can receive data about their customers from various sources:

• website
• mobile application
• call center
• offline points of sale
• other external systems

Each source may identify the same customer differently, which leads to fragmented profiles. Without a stable identifier, it is impossible to combine the customer’s actions across channels.

Example:

• The customer registered on the website and provided an email — a profile appears with customerId and email.
• Then, without logging in, they opened the mobile app to continue browsing — a new, separate profile appears without a customerId link.
• Later, they called the call center and placed an order. If the call center isn’t connected to the master system, another profile is created, again without customerId.
• The same customer made a purchase in a retail store using a loyalty card. Similarly, a new profile appears.

Thus, one person may exist in the system as four different customers.

To merge these events into a single profile, the method of creating of customer card is used — through transferring the customerId and the associated link pointers.

This method must be used when a unique user identifier is known — during authorization and registration.

Terminology

customerId

• A unique and stable customer identifier
• Issued by the master system (website, CRM, etc.) — usually upon registration
• Stable: always refers to one and only one customer
• Used to link communication channels (email, push, SMS), behavioral data, personal attributes (name, birth date), and order history

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Usage recommendations

• Use a surrogate key (e.g., UUID) instead of personal data (phone, email, card number).
• Prevent reuse of the same customerId.
• Ensure uniqueness to avoid merging different customers.

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Not recommended

• Do not send mutable data (email, phone, loyalty card) as customerId.
• Do not cache requests transferring customerId — in case of a failure, mass merging of customers under a single ID may occur.

link

• link is a string pointer to the user (e.g., phone number, loyalty card, external system ID, installId in the app, etc.).
• One customerId may have multiple link pointers.
• Used for matching and subsequently merging user events.
• A link may later be reused by another person (for example, if a phone number or card changes ownership).

If customerId is not passed, data for each link forms a separate profile. Only with customerId can they be combined into a unified customer card.

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Note

When integrating via JS SDK, the link parameter is not explicitly used, but its value is represented by a cookie automatically issued to the user.

However, you can pass additional user pointers using the softLinks parameter of the Create Customer method.

Behavioral Examples in Different Scenarios