According to https://www.codingshuttle.com/blogs/spring-boot-4-a-complete-guide-to-new-features-improvements-and-why-you-should-upgrade/#a-ssl-certificate-monitoring-the-lifesaver, Spring Boot 4 provides the ability to report an app as unhealthy if its server certificate is about to expire. According to https://stackoverflow.com/questions/77380071/get-server-certificate-used-for-current-request, it should be possible in ASP.NET to detect this, if the incoming request uses HTTPS.
According to https://www.codingshuttle.com/blogs/spring-boot-4-a-complete-guide-to-new-features-improvements-and-why-you-should-upgrade/#a-ssl-certificate-monitoring-the-lifesaver, Spring Boot 4 provides the ability to report an app as unhealthy if its server certificate is about to expire.
According to https://stackoverflow.com/questions/77380071/get-server-certificate-used-for-current-request, it should be possible in ASP.NET to detect this, if the incoming request uses HTTPS.