I use AWS to run a web application, which supports custom domains and subdomains. I am using AWS certificate manager to generate and manage certificates.

Well, say my application is available under https://myapplication.com , I can use my certificate manager to generate certificate for my domain. Also I can very well support subdomains like https://customer1.myapplication.com , https://customer2.myapplication.com etc by using a wildcard certificate like *.myapplication.com

This gets stuck when I try to support custom domains, like if I need to support https://customapplication.com or https://myapplication.custom.com. What I does is, I will configure DNS and attach the certificate to my Application Load Balancer and DNS (Route 53). But ALB has a limit of 25 certificates per node. Some workaround to support more than 25 certificates is to bring up multiple ALB and introduce a Network Load Balancer as shown in the diagram below;


If I proceed with similar architecture, I will end up with bringing up one load balancer for every 25 domains I serve in DNS. I don't think such solution is feasible.

I was reading all the blogs and documentation available online and I would like to see Is it possible to use HAProxy with Application Load Balancer and Route 53 to enable more than 25 certificates in AWS?

I am adding links below for reference.




2 Answers 2


At least in US-East-1, we were able to request 50 certs per ALB, and 100 SAN names per cert = up to 5k unique names. Try asking for a quota increase. We got it, and it's not in the documentation that it goes any higher than 25 certs per ALB.


You can now ask for increasing your Quote. I did few weeks back and got it increased to 100.

Another approach would be to use a NLB -> Caddy Server -> ALB -> App servers.

Caddy server can automatically generate certificates for you.

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