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IPv6 in Common Crawl

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✓ checked 13 October 2026 · source: Common Crawl crawl statistics (Apache-2.0) · method · caveats · download the data

31.84% of Common Crawl’s fetches in its September 2026 crawl went over IPv6, against 0.54% in February 2026. The September crawl (CC-MAIN-2026-39) made 823.7 million IPv6 fetches out of 2.59 billion with a recorded IP version. Common Crawl says the jump came from a change to its crawler’s HTTP library, not from a change on the web.

IPv6 share, Sep 2026 crawl 31.84%HTTP/2 share, Sep 2026 78.6%crawls covered 22

Headline numbers

  1. A step change in March 2026. The IPv6 share went from 0.54% in CC-MAIN-2026-08 to 31.42% in CC-MAIN-2026-12, about 54 times as many IPv6 fetches. In all 7 crawls from March 2026 on, it has stayed between 31.42% and 32.49%. Before March it never passed 0.63%.
  2. Common Crawl’s explanation: its March 2026 announcement says an upgrade of the OkHttp library turned on Happy Eyeballs (RFC 6555), which races IPv4 and IPv6 connections and gives IPv6 a small head start. It says this raised IPv6 fetches “from 0.5% to around 31%”.
  3. HTTP/2 and TLS 1.3 kept climbing slowly. HTTP/2 carried 78.6% of fetches with a recorded HTTP version in September 2026, up from 72.3% in December 2024. TLS 1.3 went from 82.8% to 90.2% of TLS fetches.

IPv6 share by crawl

IPv6 share of Common Crawl fetches, by crawlCC-MAIN-2024-51CC-MAIN-2024-51: 0.25%0.25%CC-MAIN-2025-05CC-MAIN-2025-05: 0.25%0.25%CC-MAIN-2025-08CC-MAIN-2025-08: 0.33%0.33%CC-MAIN-2025-13CC-MAIN-2025-13: 0.33%0.33%CC-MAIN-2025-18CC-MAIN-2025-18: 0.34%0.34%CC-MAIN-2025-21CC-MAIN-2025-21: 0.45%0.45%CC-MAIN-2025-26CC-MAIN-2025-26: 0.54%0.54%CC-MAIN-2025-30CC-MAIN-2025-30: 0.63%0.63%CC-MAIN-2025-33CC-MAIN-2025-33: 0.63%0.63%CC-MAIN-2025-38CC-MAIN-2025-38: 0.61%0.61%CC-MAIN-2025-43CC-MAIN-2025-43: 0.60%0.60%CC-MAIN-2025-47CC-MAIN-2025-47: 0.59%0.59%CC-MAIN-2025-51CC-MAIN-2025-51: 0.52%0.52%CC-MAIN-2026-04CC-MAIN-2026-04: 0.55%0.55%CC-MAIN-2026-08CC-MAIN-2026-08: 0.54%0.54%CC-MAIN-2026-12CC-MAIN-2026-12: 31.42%31.42%CC-MAIN-2026-17CC-MAIN-2026-17: 32.24%32.24%CC-MAIN-2026-21CC-MAIN-2026-21: 31.55%31.55%CC-MAIN-2026-25CC-MAIN-2026-25: 32.46%32.46%CC-MAIN-2026-30CC-MAIN-2026-30: 32.08%32.08%CC-MAIN-2026-34CC-MAIN-2026-34: 32.49%32.49%CC-MAIN-2026-39CC-MAIN-2026-39: 31.84%31.84%
IPv6 fetches as a share of fetches with a recorded IP version. Pink: crawls after the March 2026 crawler change. Source: Common Crawl crawl statistics.

Context

The counters first appear in the December 2024 crawl (CC-MAIN-2024-51), when Common Crawl said its crawler could now reach IPv6-only websites but still preferred IPv4. At that point IPv6 carried 0.25% of fetches. So the figures show how often CCBot ended up on IPv6, which depends on its own connection settings as well as on how many sites support IPv6. They are not a measure of IPv6 adoption across the web.

The same statistics also count robots.txt denials: see Common Crawl Robots.txt Denials, 2016–2026.

Every crawl with IP counters

CrawlIPv4 fetchesIPv6 fetchesIPv6 shareHTTP/2 shareTLS 1.3 share
CC-MAIN-2026-391,763,630,004823,696,08131.84%78.6%90.2%
CC-MAIN-2026-341,720,286,489828,024,20632.49%77.5%89.5%
CC-MAIN-2026-301,738,353,307821,105,98532.08%77.5%89.1%
CC-MAIN-2026-251,678,221,484806,620,99832.46%76.5%89.0%
CC-MAIN-2026-211,752,265,702807,802,16531.55%76.6%88.7%
CC-MAIN-2026-171,754,184,699834,469,63332.24%76.2%88.0%
CC-MAIN-2026-121,604,109,903734,918,58231.42%75.3%86.1%
CC-MAIN-2026-082,532,138,47513,639,5330.54%75.2%86.0%
CC-MAIN-2026-042,697,415,92214,964,6420.55%75.4%85.7%
CC-MAIN-2025-512,524,019,25413,171,9380.52%73.6%85.1%
CC-MAIN-2025-472,662,146,10515,934,0550.59%73.7%85.0%
CC-MAIN-2025-433,005,102,96618,102,7990.60%76.3%86.4%
CC-MAIN-2025-382,781,126,21717,076,5060.61%75.6%86.1%
CC-MAIN-2025-332,823,211,68318,026,0230.63%75.1%85.7%
CC-MAIN-2025-302,817,216,60117,876,0100.63%74.4%85.5%
CC-MAIN-2025-262,794,169,95515,221,1460.54%73.9%85.0%
CC-MAIN-2025-212,891,292,64413,084,1430.45%74.3%84.7%
CC-MAIN-2025-183,214,992,17210,848,8760.34%73.5%84.0%
CC-MAIN-2025-133,203,129,52510,634,3700.33%72.9%84.7%
CC-MAIN-2025-083,128,130,57610,219,0070.33%72.8%83.6%
CC-MAIN-2025-053,491,098,6488,898,0760.25%73.8%83.7%
CC-MAIN-2024-513,057,743,9677,585,8390.25%72.3%82.8%

Method

Common Crawl publishes crawler counters for every crawl in its cc-crawl-statistics repository on GitHub. On 13 October 2026 we downloaded all crawl files and kept the 22 that contain the ip_address_version counters (CC-MAIN-2024-51 to CC-MAIN-2026-39). For each crawl, the IPv6 share is the IPv6 counter divided by the sum of the IPv4 and IPv6 counters. The HTTP/2 and TLS 1.3 shares are computed the same way from the http_protocol_version and tls_protocol_version counters. A separate script recomputes every number from the raw files.

Caveats

  • The shares use fetches with a recorded IP version as the denominator, not all fetch attempts. Measured against all 3.49 billion fetch attempts in September 2026, IPv6 fetches were 23.6%.
  • These are counts of URL fetches, not of sites, and the crawler’s choice of URLs changes from crawl to crawl.
  • The March 2026 jump reflects a crawler change, so crawls before and after it aren’t directly comparable.
  • The figures describe one crawler running in one cloud network. Other clients will see different shares.

Download the data

Cite as: ProxyPicker, “IPv6 in Common Crawl, 2024–2026”, 13 October 2026, https://proxypicker.com/common-crawl-ipv6/. Data: Common Crawl crawl statistics.

Related: Common Crawl Robots.txt Denials · AI-Crawler & llms.txt Census.

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