How to Set ECID to an eVar in Adobe Analytics (Client-side & Server-side)

Updated: December 19, 2025

The Experience Cloud ID (ECID) is the primary identifier for users in Adobe Analytics. When deploying Adobe Analytics, ECID is commonly assigned to an eVar to enable cross-session and cross-device analysis.

The method for setting ECID depends on whether you are using client-side or server-side tracking.

Client-Side Tracking（Dynamic Variable）

When deploying client-side tracking, the recommended approach is to use dynamic variables to map ECID to an eVar.

Common Mistake

Some implementations use the Experience Cloud ID Service built-in data element for ECID directly as an eVar.:

While this approach does capture the ECID, it often results in “Unspecified” values in reports.

Why this happens:

• “Unspecified” indicates that the variable is undefined or unavailable at the time the hit is sent.
• Using the built-in data element alone does not guarantee the ECID has been resolved before the eVar is set.

Correct Configuration

Instead, use dynamic variables. In client-side tracking, the ECID is available in the mid variable by default.

mid is actually ECID, map mid to your desired eVar using dynamic variables:

This ensures that the eVar consistently receives the ECID value, and “Unspecified” will no longer appear.

Server-Side Tracking (Processing Rules)

For server-side deployments, you might be tempted to use the official getIdentity method to retrieve ECID.

⚠️ A common issue arises when new users trigger hits before their ECID has been returned by the Identity Service. This can also result in “Unspecified” values.

Recommended Approach：Use Processing Rules to set ECID on the server side, the ECID is available at a.x.identityMap.ecid.0.id，map this value to your eVar within the processing rules configuration

This method ensures that all server-side hits correctly capture ECID, eliminating “Unspecified” values in your reports.

Summary