Expect-CT

HTTP response header

The Expect-CT header allows sites to opt in to reporting and/or enforcement of Certificate Transparency requirements which prevents the use of misissued certificates for that site from going unnoticed

Header usage statistics

Expect-CT response header information and usage statistics.
Websites using header Expect-CT175,228
Percentage of websites that use Expect-CT header0.22%
Total discovered header values6,547
Header uses directivesYes
Header values are unique or randomNo
Most popular in the country United States

Expect-CT directives (3 total)

  • enforce
  • max-age
  • report-uri

Expect-CT Directives

Expect-CT directives value information and usage statistics
DirectiveShareWebsites countUnique Values
max-age99.12%173,68058
enforce69.69%122,12535
report-uri17.29%30,305386

Connected technologies

Technologies that utilize the header
Cloudflare, category Content Delivery Networks, total 10,469,607 websites
Replit, category Dev Tools, total 236 websites

Expect-CT header usage distribution by website rank



Geographical Distribution

Header usage distribution by websites across the globe.



Websites utilizing Expect-CT

List of websites that use Expect-CT header
DomainCountryRankContacts
www.afternic.com Netherlands52
www.godaddy.com United States97
finance.yahoo.com United States102
tw.yahoo.com United States162
yahoo.com.tw United States210
www.yahoo.com United States416
See full domain list

Common header values

List of top common Expect-CT header values
Header valueValue prevalence
max-age=7776000, enforce24.27%
max-age=015.53%
max-age=86400, enforce12.31%
enforce, max-age=216007.08%
max-age=31536000, report-uri="http://csp.yahoo.com/beacon/csp?src=yahoocom-expect-ct-report-only"4.20%
enforce, max-age=86400, report-uri="https://hpage-report.uriports.com/reports/enforce"1.52%
max-age=864001.42%
enforce, max-age=315360001.30%
enforce, max-age=3001.28%
max-age=5184000, enforce1.13%
enforce; max-age=2592000;1.03%
enforce; max-age=36001.02%
enforce, max-age=36001.00%
enforce,max-age=25920000.93%
enforce, max-age=864000.90%
max-age=0, report-uri="/report-expect-ct-violation"0.88%
enforce, max-age=432000.87%
enforce; max-age=300.85%
max-age=315360000.68%
enforce, max-age=300.68%