Get the full resource as a downloadable PDF: How does AI traffic show up in analytics [PDF].
The other day, I was thinking about resources I wished someone had put together and I realised I wanted someone to collate the current state of play of how traffic referred from different AI sources shows up in server logs and web analytics.
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I (with some agentic support) aggregated research and pulled it together into a table to summarise how it works in mid-2026. It's a fast-changing area, and some details may vary in different circumstances, so validate specific details before relying on them, and let me know if you spot any mistakes:
← Scroll to see all columns →
|
Platform
|
Surface / Client | Raw HTTP Referrer | GA4 source / medium | GA4 Default Channel | Notes |
|---|---|---|---|---|---|
|
ChatGPT
|
Web — desktop browser | https://chatgpt.com/ | chatgpt.com / referral —or— chatgpt.com / (not set) if UTM-tagged |
Referral or Unassigned | Referrer passes on direct clicks. Since mid-2025 OpenAI appends utm_source=chatgpt.com to citation links but not utm_medium — so UTM-tagged visits land as Unassigned, not Referral, in GA4's default grouping. |
| Mobile web browser | https://chatgpt.com/ | chatgpt.com / referral | Referral | Consistent with desktop web. | |
| iOS / Android app | None — stripped (OS handoff) | (direct) / (none) | Direct (dark) | OS handoff to system browser strips referrer. Copy-paste also dark. Near-100% dark. | |
| Desktop app — Atlas (macOS) | None — stripped (sandboxed Chromium) | (direct) / (none) | Direct (dark) | Impersonates Chrome user agent, so bot filters miss it. | |
|
Claude
|
Web — desktop browser | https://claude.ai/ (intermittent) | claude.ai / referral | Referral | Referrer passed inconsistently. No UTM params from Anthropic. Low reliability. |
| Mobile web browser | https://claude.ai/ (intermittent) | claude.ai / referral | Referral | Same inconsistency as desktop web. | |
| iOS / Android app | None — stripped (SFSafariViewController) | (direct) / (none) | Direct (dark) | iOS sandboxes content via SFSafariViewController, stripping the origin. Near-100% dark. | |
| Desktop app (Electron) | None — stripped (OS handoff) | (direct) / (none) | Direct (dark) | External links use shell.openExternal() — referrer lost on handoff to system browser. | |
|
Gemini
|
Web — browser (desktop & Chrome sidebar) | https://gemini.google.com/ | gemini.google.com / referral | Referral | Referral not Organic Search, despite the google.com domain. No standalone desktop app. |
| Mobile web browser | https://gemini.google.com/ | gemini.google.com / referral | Referral | Moderate reliability; similar to desktop web. | |
| iOS / Android Gemini app | None — stripped, or google.com via Google App routing | (direct)/(none) or google / organic | Direct or Organic Search | Worst mobile performer. ~91% dark; a minority bleed into google / organic via Google App routing. | |
|
AI Overviews
|
Web — desktop browser | https://www.google.com/search?… (same as organic) | google / organic | Organic Search | Indistinguishable from regular organic in GA4 and GSC. |
| Mobile browser / Google app | https://www.google.com/search?… | google / organic | Organic Search | Same as desktop. Visible in GSC via Search Appearance filter only. | |
|
AI Mode
|
Web — desktop browser | None — stripped (noreferrer), or google.com on minority of clicks | (direct)/(none) or google / organic | Direct or Organic Search | Primarily Direct. noreferrer attribute strips referrer on most clicks despite Google's stated May 2025 fix. |
| Mobile browser / Google app | None — stripped, or google.com on minority of clicks | (direct)/(none) or google / organic | Direct or Organic Search | Same as desktop. Primarily Direct; some sessions appear as Organic Search. | |
|
Perplexity
|
Web — desktop browser | https://www.perplexity.ai/ | perplexity.ai / referral | Referral | Best-performing AI platform. Consistently passes referrer data. |
| Mobile web browser | https://www.perplexity.ai/ | perplexity.ai / referral | Referral | Good reliability; similar to desktop web. | |
| iOS / Android app | https://www.perplexity.ai/ (~70% of sessions) | perplexity.ai / referral (~70%) | Referral (~70%) / Direct (~30%) | ~30% dark vs ~70–91% for other AI apps. Best-in-class mobile attribution. | |
| Perplexity Comet (AI browser) | https://www.perplexity.ai/ | perplexity.ai / referral | Referral | Unlike ChatGPT Atlas, Comet passes referrer data reliably. |
Sources: MarTech · Search Engine Land · Loamly · Ahrefs · Passionfruit · Lawrence Hitches. Fast-moving area - verify details before relying on them.
Of course, these measurement and attribution issues only exacerbate the changing value of a click.
I hope you find it useful. Don't forget, you can download it as a PDF: How does AI traffic show up in analytics [PDF]. Let me know how you use it.
