_clck is set by Microsoft Corporation via Microsoft Clarity to identify returning users across sessions.
Microsoft Corporation — loaded via the Microsoft Clarity behaviour analytics script.
What it does
Stores a unique user ID so Clarity can stitch together heatmaps, session recordings, and engagement metrics across multiple visits from the same browser.
Duration
1 year.
Consent type
Analytics / non-essential — requires user consent under GDPR and similar privacy laws.
Part of the Microsoft Clarity suite alongside _clsk. Remove via browser settings or block the Clarity script. See how to inspect cookies.