Understanding Network_userid and Domain_userid in Snowplow: A Technical Deep Dive

Network_userid and domain_userid are key identifiers in Snowplow's tracking system, crucial for monitoring user interactions across sessions and domains. Network_userid is generally a third-party cookie-based identifier that remains consistent across domains when third-party cookies are allowed or can be stored as a first-party cookie if a custom collector domain is used. Domain_userid, on the other hand, is a first-party cookie-based identifier specific to a domain or subdomain, which can vary due to different browsers, devices, cookie expiry, and cross-domain tracking limitations. Discrepancies between these identifiers arise when users switch browsers, clear cookies, or interact with multiple domains without proper cross-domain tracking. Snowplow helps manage these discrepancies by offering robust tracking capabilities, allowing data teams to configure cross-domain tracking effectively and align cookie lifetimes, thereby minimizing inconsistencies. It also provides enriched events and advanced data modeling to resolve different domain_userid values to a single network_userid, enhancing user attribution and multi-touch analysis. Best practices include using a custom collector domain, implementing cross-domain tracking, aligning cookie expiry settings, and employing data models that link network_userid to domain_userid values to ensure comprehensive user journey analysis.