How many subdomains we can create in Route 53 AWS DNS service?

Question

In my application, I'm giving a subdomain (like user.domain.com) to each account. So, I'm planning to use AWS Route 53 for routing subdomains to my application. Is there any maximum limit of subdomains in Amazon Route 53. Thanks in advance!

Answer 1

This might be relevant or not depending on your use case, but if you expect a large number of users and want to assign a custom subdomain per user, then the limit of 10,000 is probably not sufficient for you.

Your other option is to create a CNAME record with a wildcard subdomain, something like *.domain.com, and point the record to your application, this is now supported by AWS Route 53 and will support all possible subdomains.

The drawback is that subdomains that are not registered will also be directed to your application (like random-str.domain.com), so you'll need to do your validation outside of Route 53. Maybe call an API to validate from your frontend app

Answer 2

I'm giving a subdomain (like user.domain.com) to each account

You should revise your application design what If you users reached to million? and what if you want to migrate your DNS in future also subdomain maximum limit varies from service provider to service provider.

So generalize solution cloud be like all subdomain will point to a single endpoint (Load balancer) and your core backend will check DNS and then load custom response base on the domain, normally login page for which you can save custom logo etc against domain name and load these resources base on domain.

High-level architecture

So same case for a big cloud service provider, for example, slack, which provides subdomain for each user but do we think that slack manages route53 record for each users?

how-slack-works

Or you can simply do nslookup, for thousand domain you will get the same backend IP.

slacker:~$ nslookup acmeinc.slack.com
Name:   acmeinc.slack.com
Address: 13.228.49.204

slacker:~$ nslookup www.slack.com
Name:   www.slack.com
Address: 13.228.49.204

Answer 3

The Route53 limits and quotas are listed here.

The limits are not expressed directly in number of subdomains, but rather in number of records and hosted zones, among other things.

Therefore, there is 10,000 records per hosted zone, but it can be increased. Also you can have 500 hosted zones per account.