Cloudflare Radar is a free public website and application programming interface (API) through which Cloudflare publishes aggregated measurements of what crosses its network: traffic volumes by country and network, the share of requests made by bots, the behaviour of artificial intelligence (AI) crawlers, cyberattacks, routing incidents and internet outages. It exists because Cloudflare, a content delivery network (CDN) and domain name system (DNS) provider, sits between a large share of websites and their visitors, and so sees patterns that no single site owner can. Cloudflare says that position covers roughly a fifth of web traffic. Radar has become one of the most quoted sources on how much of the web is now read by machines.

Where the data comes from

Radar draws on two main pools. The first is the HTTP traffic that passes through Cloudflare's reverse proxies on behalf of its customers. When Radar launched, Cloudflare said it handled on average 18 million HTTP requests and 6 million DNS requests every second, and that about 1 billion unique IP addresses connected to its network, according to the launch post by product director Marc Lamik. The second is aggregated and anonymised query data from 1.1.1.1, Cloudflare's public DNS resolver, which powers rankings of domains, internet services and top-level domains, according to the Radar about page.

Routing data comes from outside Cloudflare. The about page lists RIPE NCC's Routing Information Service and the University of Oregon's RouteViews for Border Gateway Protocol (BGP) feeds, with PeeringDB, APNIC and CAIDA used for network and population data. Attack data comes from Cloudflare's own distributed denial-of-service (DDoS) defences and firewalls.

Licensing differs by format. Embeddable charts are published under Creative Commons CC BY 4.0, while data pulled through the API or downloaded directly is released under CC BY-NC 4.0, which bars commercial reuse without separate permission. The API itself is free, according to Cloudflare's developer documentation, and requires a Cloudflare API token.

How bots and AI crawlers are counted

For advertisers and publishers, the most consequential part of Radar is its bot reporting. Every request Cloudflare sees receives a bot score from 1 to 99. Radar groups scores of 1 to 29 as "likely automated" and 30 to 99 as "likely human", according to Cloudflare's bot classes documentation. The score is a probability, not a verified identity.

A separate layer tracks named crawlers. Radar lists verified bots - automated agents whose operators Cloudflare has confirmed - and breaks AI crawlers out by operator and by declared purpose: training, search and user-initiated actions. The AI bot list was built on the community-maintained ai.robots.txt project, according to a February 2025 Cloudflare blog post by David Belson. Radar also scans the robots.txt files of its top 10,000 domains each week to report which AI user agents are allowed or disallowed, broken down by site category.

The best-known output is the crawl-to-refer ratio, added to Radar on July 1, 2025. It divides HTML page requests from a platform's crawlers by HTML requests whose Referer header names that platform, normalised to one referral, according to the Cloudflare blog post by David Belson and Sam Rhea. All of an operator's crawlers are pooled under one name, and referrals from Google's network (autonomous system 15169) are excluded because Chrome's prefetching would otherwise count machines as readers. For June 19 to 26, 2025, Anthropic's ratio stood at about 70,900 to one and Mistral's at 0.1 to one. The crawl-to-referral ratio explainer covers the metric in more detail.

The API, rankings and outage tracking

Almost every Radar chart has an API endpoint. Endpoints added in February 2025 cover daily rankings of internet services, including generative AI tools, derived from 1.1.1.1 queries.

Radar Domain Rankings, launched on September 30, 2022, estimate "the relative size of the user population" that reaches a domain, rather than raw traffic. Only the top 100 are given individual ranks; beyond that, domains are placed in unordered buckets running from the top 200 to the top 1,000,000, according to the Cloudflare announcement by Celso Martinho and Sabina Zejnilovic.

The Cloudflare Radar Outage Center, launched the same day, logs disruptions by location, network, type, likely cause and start and end times, with CSV downloads. Its likely causes rest on "publicly available information", according to the launch post by David Belson and Stanley Chiang. Radar's charts became a reference point during events such as Iran's nationwide shutdown in January 2026, and Cloudflare publishes quarterly disruption summaries such as its second-quarter 2025 review.

Origin and evolution

Radar launched during Cloudflare's Birthday Week in late September 2020 with three parts: Internet Insights, Domain Insights and IP Insights. PPC Land described it at the time as a free dashboard comparable to Alexa and SimilarWeb, with last-hour, 24-hour and seven-day views.

Radar 2.0 followed on September 30, 2022, the second anniversary, adding new navigation, global search and the public API, according to the Cloudflare announcement by João Sousa Botto, David Belson and Ricardo Baeta. Route leak detection arrived in 2022 and origin hijack detection and the URL Scanner in 2023. In September 2024 Radar added a chart of TCP connection anomalies, and the same month a graph of AI bot and crawler traffic appeared on its Traffic page.

That AI graph moved to a dedicated AI Insights page on February 4, 2025. On October 27, 2025, Radar added analytics for more than 1,400 top-level domains, ranked by DNS Magnitude. In April 2026 the AI Insights page gained widgets for adoption of AI agent standards, HTTP status codes returned to AI bots and the size saved by serving Markdown instead of HTML.

Why it matters for marketers

Radar is one of the few free, continuously updated sources on automated traffic at web scale, and its figures increasingly frame debates about publisher economics. Cloudflare's 2025 Year in Review, its sixth, found that humans generated 43.5 per cent of HTML requests, non-AI bots 47.9 per cent and AI crawlers 4.2 per cent, with Googlebot separately at 4.5 per cent, as PPC Land reported in December 2025. By early June 2026, Radar showed bots at 57.4 per cent of HTML traffic, with training crawlers alone at 50.6 per cent.

Those shares matter to advertising in three ways. Bot requests inflate audience pools built from site visits, which can distort retargeting; agencies have linked bot-heavy traffic to CPMs rising about 20 per cent once audiences are cleaned. Crawl-to-refer data gives publishers a number for what AI platforms take versus what they send back: OpenAI's ratio stood at 1,091 to one in July 2025, while Anthropic's fell from 286,930 to 38,065 between January and July, according to data PPC Land covered on September 1, 2025. And the figures feed licensing arguments: Matthew Prince, Cloudflare's chief executive, told The Verge's Decoder podcast that "bots don't click on ads", as PPC Land reported.

Limitations and disputes

Radar measures Cloudflare's network, not the internet. Its sample over-represents sites that chose Cloudflare, and the company's own domain rankings post concedes possible bias from "the geography of Cloudflare's customers and users". Cloudflare also does not define the denominator behind its one-fifth claim; PPC Land noted in October 2026 that the company alternates between "web" and "sites".

Bot classification is probabilistic and the models are proprietary, so outside researchers cannot reproduce the scores. The crawl-to-refer ratio has documented gaps. Native apps, including Claude's, often send no Referer header, so Cloudflare itself says Anthropic's ratio may be overstated. Training crawlers have no referral mechanism at all, which makes judging them by referrals contestable. Cloudflare's accusation that Perplexity used undeclared crawlers, which Perplexity disputed, shows how attribution by user agent can be contested.

There is also a conflict of interest. Cloudflare sells bot management, AI crawler blocking and pay-per-crawl tools, so the measurements that describe the problem are published by a vendor of the remedies. None of Radar's figures is independently audited. Even Cloudflare's numbers shift: Prince's quoted Google ratio and Radar's tables have not been reconciled.

Not the same as

  • Attribution Business Insights: a dashboard for Cloudflare Bot Management customers, launched July 1, 2026, that shows crawl-to-referral ratios for a single customer's site. Radar shows network-wide aggregates to anyone.
  • Autonomous system: a network with its own routing policy, identified by a number such as AS15169. Radar reports traffic and routing by autonomous system, but the term describes networks, not the observatory.
  • Traffic estimation panels: services such as SimilarWeb, and formerly Alexa, estimate visits to individual sites from panels and other inputs. Radar's domain rankings estimate relative user population from DNS queries and publish no visit counts.
  • Cloudflare CDN: the content delivery network that generates most of Radar's data. Radar reports on it but does not route or cache anything.

Recent developments

On October 8, 2026, Cloudflare redesigned Radar's landing page around a world map, putting outages and traffic first, after users found the old layout intimidating. No usage figures accompanied the change. Earlier, in July 2026, Cloudflare agreed to give OpenAI network signals on content freshness and traffic quality, a pilot that does not use Radar but draws on the same vantage point. Late in September 2026 Prince said automated traffic had passed human traffic on Cloudflare's network in May 2026 and predicted machines would generate about 1,000 times human volume within five years, "with the giant caveat that I've gone wrong so far in every prediction that I've made on this". Proposals such as Web Bot Auth, which lets crawlers sign their requests, could eventually sharpen how Radar separates declared agents from impostors.

Timeline

  • September 30, 2020: Cloudflare launches Radar with Internet Insights, Domain Insights and IP Insights.
  • December 2020: first Cloudflare Radar Year in Review (the 2025 edition is the sixth).
  • September 30, 2022: Radar 2.0 launches in beta with a public API, the Radar Outage Center and Radar Domain Rankings.
  • 2022: route leak detection added.
  • 2023: origin hijack detection and the URL Scanner added.
  • September 2024: TCP connection anomaly chart and an AI bot and crawler traffic graph added.
  • February 4, 2025: dedicated AI Insights page launches with generative AI service rankings and robots.txt analysis.
  • July 1, 2025: crawl-to-refer ratio added to AI Insights.
  • August 29, 2025: Cloudflare publishes seven months of per-operator crawl-to-refer data.
  • October 27, 2025: top-level domain analytics for more than 1,400 TLDs launch.
  • December 15, 2025: 2025 Year in Review puts AI crawlers at 4.2 per cent of HTML requests.
  • April 17, 2026: AI Insights adds agent standards adoption, AI bot response status and Markdown savings widgets.
  • June 3, 2026: Radar data shows bots at 57.4 per cent of HTML traffic.
  • October 8, 2026: Radar landing page redesigned around a world map.

Summary

Who: Cloudflare operates Radar; its data is used by publishers, advertisers, journalists, researchers, civil society groups and policymakers.

What: A free public observatory and API reporting traffic, bot and AI crawler activity, attacks, routing incidents, domain rankings and outages seen on Cloudflare's network.

When: Launched on September 30, 2020, expanded with Radar 2.0 and the API in September 2022, AI Insights in February 2025 and the crawl-to-refer ratio in July 2025, and redesigned on October 8, 2026.

Where: At radar.cloudflare.com and through the Radar API, drawing on Cloudflare's global network and its 1.1.1.1 resolver.

Why: Cloudflare's position in front of a large share of websites lets it publish aggregate views no single site can produce, though the figures are self-reported, unaudited and limited to its own customer base.