Genesys Cloud's authenticated web messaging enables a single customer view by consolidating different identifiers into one external contact record and linking interactions across supported channels. The platform automatically stitches interactions to existing contacts when identifiers such as phone numbers, email addresses, or social IDs match, allowing agents to view all interactions for a contact across divisions. Genesys Cloud provides four contact types for identity resolution: Identified contacts are auto-linked when a single match is found; Ephemeral contacts are temporary records expiring after 60 days when no match exists; Canonical contacts merge multiple records into a single contact; and Curated contacts become searchable after agent or API linking. To implement authenticated web messaging, users must enable Authentication in Messenger Configuration through the Behavior settings, then deploy the configuration with identity resolution parameters. Identity resolution is configured by navigating to the Identity Resolution page, selecting the Web Messenger tab, enabling the toggle for the authenticated deployment, ensuring Merge Contacts is enabled, and selecting an external source. Required permissions include WebDeployments, Messaging, Authenticate, and Routing identity resolution access, plus External Contacts Settings Edit permission for controlling division assignment of manually created contacts. Genesys Cloud uses external IDs supplied by external sources in its identity resolution algorithm to identify contacts, with optional division-based resolution for organizations that require it. The platform performs identity resolution for authenticated web messaging through different mechanisms depending on configuration settings: when authentication is off with merge contacts disabled, contacts are stitched using cookie ID only; when authentication transitions from off to on with merge contacts enabled, an external source must be selected to stitch external contacts by external ID, otherwise the system falls back to alternative identifiers like email or phone number; when authentication transitions from on to off with merge contacts disabled, the external source is cleared and contacts are stitched using cookie ID only, with a warning message displayed. The identity resolution process is critical for maintaining accurate contact identification and enabling single customer view functionality across authenticated web messaging interactions.