Which of the top 1,000 websites get the most visits from AI chatbots, and which chatbot sends them (September 2026)

Chatbots now link to their sources, and people click those links. Similarweb tracks those clicks as a traffic channel of their own, "AI chatbots", next to organic search, social and the rest. So how big is that channel for the busiest sites on the web, which sites get the most from it, and which chatbot sends it?

On 18 October 2026 we took the Tranco list of the most popular websites (list 8PX8V), removed infrastructure host names, and looked up Similarweb's traffic estimates for the top 1,300 domains. We kept the first 1,000 that had an estimate, down to Tranco rank 1,242. All the figures below are Similarweb estimates for September 2026, the latest month it had published. They are modelled, not measured.

Five findings:

• AI chatbots sent 0.52% of all visits. The 1,000 sites had about 267 billion visits in September, and 1.37 billion came from AI chatbots. The typical (median) site got 0.53% of its visits that way. 970 of the 1,000 sites had some AI chatbot traffic.
• Organic search sent 28 times as much. Search sent 14.6% of all visits and social 4.3%, 8 times the AI figure. AI chatbots sent more visits than organic search at just 4 sites, and more than social at 56. They did beat paid search at 591 of the 1,000 sites.
• ChatGPT was the top AI referrer at 718 of 793 sites (91%). Similarweb ranks the chatbots for 793 of the sites. Gemini came first at 41, Claude at 14 and Perplexity at 13. Gemini came first at YouTube, and at chatgpt.com, where ChatGPT itself isn't in the ranking.
• Research, government and reference sites get the biggest share. Leaving out AI companies' own sites, oecd.org (8.9%), nist.gov (7.2%) and who.int (6.8%) had the highest share of visits from AI chatbots. Government sites as a group got 1.10%, twice the average, and news sites 0.28%, about half.
• google.com got the most AI chatbot visits of any site: about 511 million, 37% of the total. The 20 sites with the most AI chatbot visits took 70% of all of them.

AI chatbots next to the other channels

Similarweb splits each site's visits into ten channels. Across all 1,000 sites, weighted by visits, AI chatbots are the second-smallest:

Similarweb estimates, 1,000 domains, 266.7 billion visits, weighted by visits. AI chatbots highlighted. Table below.

Similarweb estimates, September 2026, 1,000 domains, 266.7 billion visits. "Share of all visits" adds up every site's visits, so google.com (85 billion) weighs heavily; "median site" is the middle site for that channel.

The median column tells a slightly different story from the pooled one. For the typical site, AI chatbots already send more visits than paid search, affiliates or paid social. Paid search is concentrated on a few sites: it is 0.9% of all visits but only 0.2% at the median site.

Most sites sit close to the median. 30 of the 1,000 had no AI chatbot visits at all, 437 got under 0.5%, 247 got 0.5% to 1%, 192 got 1% to 2%, 77 got 2% to 5% and 17 got 5% or more.

Two of the biggest reference and discussion sites get less than the median. Wikipedia got 0.12% of its 3.4 billion visits from AI chatbots (about 4 million) and 76% from organic search. Reddit got 0.22% (about 8.4 million) and 56% from organic search.

The sites with the highest share from AI chatbots

The 20 sites with at least 1 million monthly visits that got the biggest share of their visits from AI chatbots. We left out AI companies' own sites, which we list further down.

Similarweb estimates, September 2026. 747 of the 1,000 sites had at least 1 million visits. Rank is the order in this table, not the Tranco rank.

The pattern is clear. Most of the 20 are journals and research publishers, international bodies or government agencies: places that publish the facts and studies an answer rests on. They also get a lot of organic search traffic, between 34% and 55%, so chatbot visits come on top of strong search, not instead of it. stripe.com is the exception: little organic search, and Grok ranked as its top AI referrer.

nih.gov is the only site on both lists. At 5.5% of 177 million visits, it got about 9.7 million visits from AI chatbots, the 16th most of any site in the sample.

The sites with the most visits from AI chatbots

In raw numbers, the biggest sites win. google.com gets only 0.6% of its visits from AI chatbots, but 0.6% of 85 billion is about 511 million, 37% of every AI chatbot visit in the sample.

AI chatbot visits = the site's estimated September visits × its AI chatbot share, both from Similarweb. The top 20 add up to 70.1% of the 1.37 billion AI chatbot visits in the sample.

The chatbot companies send each other plenty of visits. chatgpt.com got about 62 million visits from other chatbots, with Gemini ranked first. claude.ai got about 22 million, with ChatGPT ranked first. openai.com got 21.5% of its visits from chatbots, with ChatGPT ranked first.

Which chatbot sends the most

Similarweb ranks the chatbots that send visits to a site, but it publishes no visit count for each one. So we can count where each chatbot ranks first, not how many visits it sends. 793 of the 1,000 sites had a ranking.

Similarweb's ranking of AI referrers, September 2026, 793 sites.

ChatGPT ranks ahead of Gemini at 94% of the sites that list both. Gemini in turn ranks ahead of Perplexity at 85% and ahead of Claude at 87%. Perplexity ranks ahead of Claude at 60% of the sites that list both. ChatGPT came first in every category with at least 15 sites, at between 85% and 98% of them.

The exceptions follow a pattern:

• Claude came first at 14 sites, and all but one of them are business or developer software: okta.com, box.com, figma.com, hubspot.com, visualstudio.com, klaviyo.com, pendo.io and cloud hosting addresses (run.app, on.aws, ovh.net), plus anthropic.com.
• Perplexity came first at naver.com, nytimes.com and nu.nl, and at 8 of the 36 .ru sites with a ranking, including dzen.ru, vk.ru and avito.ru.
• Gemini came first at youtube.com, chatgpt.com, google.co.jp and google.com.hk, and at book and fan-fiction sites (archiveofourown.org, wattpad.com).
• Copilot came first only at Microsoft's own live.com and cloud.microsoft. DeepSeek came first at yandex.ru.

By category

Grouped by Similarweb's top-level category (only categories with at least 15 sites):

Similarweb estimates, September 2026, weighted by visits. Similarweb top-level categories with at least 15 sites; number of sites in brackets. Table below.

Similarweb estimates, September 2026. "From AI chatbots" adds up the category's visits. 26 sites had no category and 82 sat in smaller categories; they count in the totals above but not in this table.

Government and science sites get roughly twice the average share; news, entertainment and games about half. News is the starkest: news sites get 78 visits from organic search for every visit from a chatbot, against 29 for government sites.

AI companies' own sites

We kept these out of the share ranking because a chatbot linking to its own maker answers a different question. For the record:

Similarweb estimates, September 2026. The sample also had one more AI-branded domain, chatgpt.site (7.93%), which we left out of the rankings for the same reason.

Methodology and caveats

• Domains. Tranco list 8PX8V, generated 17 October 2026 from 30 days (18 September to 17 October) of Chrome UX Report, Farsight, Majestic, Cloudflare Radar and Cisco Umbrella data, as registrable domains. We removed 74 infrastructure host names listed by hand (CDN, API and telemetry domains such as gstatic.com and akamaiedge.net), the same list as our email security study, and looked up the next 1,300. 173 had no Similarweb estimate, mostly CDN, DNS and API hosts that people don't visit directly. Three were not looked up: two .arpa names, and turkiye.gov.tr, which our tool wrongly reduced to gov.tr. The first 1,000 domains with an estimate, down to Tranco rank 1,242, are the sample.
• Traffic data. Similarweb's public estimates for September 2026, read on 18 October 2026 with our website-traffic tool (owner runs, traffic columns only). These are modelled estimates, not measurements, and Similarweb does not publish its error margins. Use them for size and direction, not exact counts. Credit: Similarweb.
• AI chatbot visits. We use the AI chatbot share from Similarweb's channel split, multiplied by the site's September visits, so AI chatbots are on the same basis as search, social and the other channels. Similarweb also publishes a separate AI-referral figure for 792 of the sites. It adds up to 1.19 billion visits and is typically 12% lower than the channel-split figure, so the totals above may run slightly high. The chatbot ranking comes from that same AI-referral data; it has no per-chatbot counts.
• Rankings. The share ranking only includes sites with at least 1 million September visits (747 of 1,000), because shares of a few thousand visits are noisy. AI companies' and AI-branded sites are listed separately. Categories are Similarweb's own.
• Reproducible. Three scripts fetch the list, run the lookups and compute every figure (results.json). The data covers websites only; no personal data was collected.

Source: Tranco list 8PX8V (tranco-list.eu); traffic estimates by Similarweb for September 2026, collected by locaihost data on 18 October 2026.

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