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What percent of domains have CAA records?
October 2026 census edition
As of October 12, 2026, 1.4% of the 329 million domains in the Defaults.Exposed census where the CAA (Certification Authority Authorization) lookup returned a determinate answer publish a CAA record restricting which certificate authorities may issue for them, 4,655,247 domains.
CAA adoption: how it is measured
It comes from the per-check pass, which runs every graded domain through the full check battery and records a pass, a fail or an undetermined result for each check independently. Every domain in the census is measured directly and counted once.
A CAA record names which certificate authorities may issue for a domain. Without one, any authority may, and nothing in the issuance process notifies the owner. It is one DNS (Domain Name System) record with no operational risk attached, which makes the adoption rate a reasonably pure measure of how many owners know it exists.
The denominator under that share is 329 million: the population where this particular check had something to read. A domain the census could not decide on is recorded as undetermined and left out of it, never counted as a failure.
It moves when operators sign zones, publish issuance restrictions, or change delegation. A large DNS provider can shift a percentage point on its own by changing one default for every customer at once. The number is recomputed from the raw evidence at every edition. What it cannot tell you is where one particular domain stands: for that, see fix your DNS records.
the full grading methodology · the underlying dataset, published open with the counts behind every percentage. If a figure here disagrees with one elsewhere on the site, the dataset is canonical and we would like to know.
CAA adoption: how to cite it
Please cite Defaults.Exposed and link this page. The citation below carries the date.
Defaults.Exposed, "What percent of domains have CAA records?" (as of October 12, 2026). https://defaults.exposed/stats/what-percent-of-domains-have-caa-records
Permalink: https://defaults.exposed/stats/what-percent-of-domains-have-caa-records · Machine-readable: /stats/s/caa-adoption.json · Licence: open data
Methodology: how we grade the internet · Source data: census data and downloads. Updated with each census edition.