If you run yourdomain.com then www.yourdomain.com and yourdomain.com are two separate websites, causing possible duplicate content issues in search engines and causing cookie security and performance issues. The best way to solve this is to redirect your domain name to www.yourdomain.com.
Additionally, it is impossible to use a CNAME record for your 'naked' domain name so you will need to configure an A record with an IP address in your DNS.
That makes your configuration inflexible and prone to errors since you always have to make sure that the A record points to the correct IP address. If you use a CNAME for your website, you will need to update the A record immediately when the CNAME changes.
We solve both issues by offering one single place where you can point your A record to, and we will issue the redirection to www.yourdomain.com. Our IP address will not change and you will never need to worry about that again.
Just point the DNS A record for your domain to 220.127.116.11 and/or your AAAA record to 2604:a880:800:10::195a:1001.
We receive the request for yourdomain.com and forward it to www.yourdomain.com, which should point to your own server like usual.
It's a pretty simple nginx configuration that just issues a 301 redirect if we do not see the hostname starting with www.
What makes this service more special is that we support the https:// protocol by auto-provisioning a LetsEncrypt certificate on the fly.
We needed a generic service like this for our hosting company DiscourseHosting and we decided to make this a public service so anyone can enjoy it - free and forever.