Referrers from AMP cache
When a page is served through an AMP cache, a click onward to your site may carry a Referer pointing at the cache host (such as a google.com AMP path) rather than the publisher who linked you. Understanding the cache hop, and tagging links, keeps AMP-mediated referrals attributable to the real source.
What this means
AMP (Accelerated Mobile Pages) content is often served from a cache rather than the publisher's own origin. When a reader is on a cached AMP page and clicks a link to your site, the navigation originates from the cache host, so the Referer can point at the cache rather than the publisher who placed the link.
This means a referral that really came from a news article or search surface can appear to come from an AMP cache host, blurring the true upstream source.
Attributing across the cache hop
Because the cache host masks the original linker, do not assume the AMP cache itself is the audience source; it is an intermediary. Where you control the outbound link inside AMP content, add UTM parameters so attribution survives the cache hop independently of the Referer.
If you publish AMP pages, ensure your own outbound links carry UTM tags, and treat AMP-cache referrer hosts as a recognised pattern rather than a new, separate referrer to celebrate.
- Referer may point at a cache host, not the publisher
- UTM tags on the outbound link survive the cache hop
- Treat the cache as an intermediary, not the true source
How it appears in analytics and logs
A Referer that resolves to an AMP cache host means the visitor was on a cached AMP version of a page when they clicked through. The cache, not the original publisher, is what the header reflects, so the true upstream source can be obscured.
Diagnostic use case
Explain referrals that point at an AMP cache host instead of the original publisher, and keep attribution correct when traffic passes through an AMP cache hop.
What WebmasterID can help detect
WebmasterID can recognise AMP-cache referrer hosts as a distinct pattern and reconcile them with your UTM tags, so a cache hop does not silently misattribute traffic to the cache provider.
Common mistakes
- Crediting an AMP cache host as the audience source instead of the original publisher.
- Assuming the Referer always reflects the linking site when AMP caching is involved.
- Leaving AMP outbound links untagged, so attribution depends entirely on a cache-masked Referer.
Privacy and accuracy notes
This concerns only the Referer header and any UTM parameters on the link. No visitor is identified. WebmasterID records the channel, not the person.
Related pages
- Referrer-Policy and missing referrers
Referrer-Policy is the web standard that controls how much of the referrer a browser sends with a request. Site owners set it via an HTTP header or a meta tag, and modern browsers default to a privacy-leaning value. Understanding the policy values explains why so many referrers arrive trimmed to the origin or missing entirely.
- Google News referrer
Google News drives traffic from its news.google.com web surface and from the Google News mobile app. Web clicks commonly pass a news.google.com referrer, while app opens can reduce or omit it. Recognising the app-versus-web split is key to attributing Google News traffic correctly.
- UTM vs referrer: which wins
When a visit carries both a referrer and UTM campaign parameters, most analytics treat the explicit UTM source as authoritative over the inferred referrer. That is usually correct: UTM tags describe intent you set deliberately, while a referrer is whatever the browser happened to send. Understanding the precedence prevents double-counting and mis-attribution.
- Campaign links
Tag AMP outbound links so attribution survives the cache hop.
Sources and verification notes
- AMP Project — How AMP pages are cachedDocuments cache serving; referrer masking is a consequence of cache-host serving.
- MDN — Referer header
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.