Google Analytics Introduces Hostname Allowlists to Stop Referral Spam

Referral spam has long been a quiet nuisance for digital reporting, skewing session counts and distorting conversion rates.

Google Analytics has introduced a hostname 'Include' data filter, allowing administrators to specify an allowlist of approved domains authorized to send event data. Any hit originating from an unlisted or empty hostname is automatically discarded before entering standard reports, replacing the need for tedious, reactive exclude lists.

For business owners, cleaner traffic data translates directly to clearer insights and more confident budget allocation.

The critical detail: the filter permanently discards unapproved hits. If your customer journey relies on third-party checkout flows, external landing pages, or dedicated subdomains, make sure every domain is mapped and included before switching it on.

Have you audited your property recently for unverified hostname traffic?

Source: Google Analytics Help, September 21, 2026.