security header test - SERP Analysis

https://securityheaders.com/

https://developer.mozilla.org/en-US/observatory

https://www.serpworx.com/check-security-headers/

https://domsignal.com/secure-header-test

https://headerscan.com/

https://www.feedthebot.org/tools/headers/

https://dnschecker.org/server-headers-check.php

https://owasp.org/www-project-web-security-testing-guide/latest/4-Web_Application_Security_Testing/02-Configuration_and_Deployment_Management_Testing/14-Test_Other_HTTP_Security_Header_Misconfigurations

https://hackertarget.com/http-header-check/