HTTP response header

Policy informing a client how long to cache the HTTPS policy and whether this applies to subdomains.

Header usage statistics

Strict-Transport-Security response header information and usage statistics.

Websites using header Strict-Transport-Security 15,334,305
Percentage of websites that use Strict-Transport-Security header 15.48%
Total discovered header values 6,157
Header uses directives Yes
Header values are unique or random No
Most popular in the country United States of America

Strict-Transport-Security Directives (3 total)

  • includesubdomains
  • max-age
  • preload

Strict-Transport-Security Directives

Strict-Transport-Security directives value information and usage statistics

Directive Share Websites count Unique Values
max-age 99.89% 15,317,718 838
includesubdomains 22.57% 3,461,539 533
preload 12.27% 1,880,905 330

Distribution by websites popularity

Strict-Transport-Security detection in the top websites by popularity

Top 10k sites 4,928 websites
Top 100k sites 37,206 websites
Top 1m sites 296,243 websites

Websites utilizing Strict-Transport-Security

List of websites that use Strict-Transport-Security header

Domain Country Rank Contacts Ireland 2 Ireland 2 United States of America 3 United States of America 4 United States of America 6 United States of America 6
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Geographical Distribution

Header usage distribution by websites across the globe.

Common header values

List of top common Strict-Transport-Security header values

Header value Value prevalence
max-age=120 20.99%
max-age=31536000 15.01%
max-age=0 13.67%
max-age=7889238 5.80%
max-age=31536000; includeSubDomains 4.09%
max-age=31536000; includeSubDomains; preload 3.99%
max-age=15768000 3.57%
max-age=31536000; preload 2.75%
max-age=31536000; 2.43%
max-age=604800 2.42%
max-age=63072000; includeSubDomains 2.33%
max-age=63072000; includeSubdomains; preload 1.89%
max-age=300 1.89%
max-age=63072000 1.69%
max-age=43200 1.29%
max-age=15768000; includeSubDomains 1.08%
max-age=31556926 0.90%
max-age=16000000 0.81%
max-age=15724800; includeSubDomains 0.69%
max-age=0; includeSubDomains 0.66%