Defaults.Exposed › Stats › Web security headers
How many websites pass every security-header check?
October 2026 census edition
As of October 12, 2026, only 1,728,228 domains (1.5% of the 116 million domains in the Defaults.Exposed census that served a web page and could be checked for every header) pass every security-header check simultaneously.
All headers passing: 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.
This figure counts sites passing every header check at once, because each of these controls closes a different narrow route and a site missing one leaves that route open. It is consistently a fraction of any individual header’s adoption.
The figure is an absolute count of domains rather than a sample scaled up. A domain the census could not decide on is left out rather than estimated.
It moves when sites add or drop response headers. These are the cheapest controls the census measures, usually one line of server or CDN (Content Delivery Network) configuration. Adoption stays low because a site without them loads and works exactly as it does with them. 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 what the headers do.
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.
All headers passing: how to cite it
Please cite Defaults.Exposed and link this page. The citation below carries the date.
Defaults.Exposed, "How many websites pass every security-header check?" (as of October 12, 2026). https://defaults.exposed/stats/how-many-websites-pass-every-security-header-check
Permalink: https://defaults.exposed/stats/how-many-websites-pass-every-security-header-check · Machine-readable: /stats/s/all-headers-pass.json · Licence: open data
Methodology: how we grade the internet · Source data: census data and downloads. Updated with each census edition.