Free Subdomains
for Developers

A subdomain is a prefix attached to a domain name, separated by a dot. For example, in myproject.is-pro.dev, the part myproject is the subdomain and is-pro.dev is the root domain.

Subdomains let different services or projects live under the same root domain while maintaining distinct addresses. They're used everywhere — www.example.com is technically a subdomain too!

With is-cool-me, you get to pick the myproject part. The root domain is managed by us, while your DNS records point to wherever you're hosting your project.

The Domain Name System (DNS) is the internet's address book. When you type a domain into a browser, DNS translates it into an IP address so your computer knows which server to contact.

Each DNS record type serves a purpose:

• A record — maps a name to an IPv4 address
• AAAA record — same, but for IPv6 addresses
• CNAME record — aliases one name to another hostname
• MX record — directs email for a domain to a mail server
• TXT record — stores arbitrary text (used for verification, SPF, etc.)
• CAA record — controls which certificate authorities can issue SSL certificates
• SRV record — points clients to a specific service endpoint
• PTR record — maps an IP address back to a hostname in reverse DNS setups

The dashboard supports A, AAAA, CNAME, MX, TXT, CAA, SRV, and PTR records, plus Cloudflare proxying for compatible records.

Use a CNAME if your host gives you a hostname (e.g., yoursite.vercel.app or username.github.io). A CNAME makes your subdomain an alias for that hostname, so it always follows if the underlying IP changes.

Use an A record if your host gives you a static IPv4 address (e.g., a VPS or dedicated server). Enter the IP directly and your subdomain resolves to that address.

Most modern platforms (Vercel, Netlify, GitHub Pages, Render) prefer CNAME records. Check your hosting provider's custom domain docs for the exact value to use.