Domain API

A Domain API is a REST (or sometimes XML-over-HTTP) API exposed by a registrar that lets you register, renew, transfer, and manage domain names programmatically. Built primarily for resellers and SaaS apps that need to issue domains as part of their product flow.

Distinct from a DNS API, which manages records inside an existing zone. A domain API operates one layer up: it's about the registration itself.

What it covers

A typical domain API has endpoints for:

• Availability check. Is example.com available?
• Pricing lookup. What does example.io cost from this registrar?
• Suggestions. Given "mybrand," suggest available alternatives.
• Register. Buy a domain. POST registrant contact info and payment, get the domain registered.
• Renew. Extend the registration.
• Transfer in. Initiate a transfer from another registrar (requires auth code).
• Transfer out. Generate an auth code so the user can transfer away.
• List domains. Inventory of what's in your account.
• Set nameservers. Point the domain at a DNS host.
• Update contacts. Change registrant/admin/tech contact info.
• Lock/unlock. Toggle the registrar-lock status.
• Privacy on/off. Toggle WHOIS privacy.

Which APIs exist

• Namecheap. XML-over-GET. Free dev sandbox, simple auth, decent docs. The hobby-friendly choice.
• GoDaddy. REST/JSON. Good docs, decent API, requires reseller agreement for production volume.
• Cloudflare. REST/JSON. Modern, well-documented. Limited TLD coverage compared to bigger registrars.
• Porkbun. REST/JSON. Small, cheap, founder-run. Cleanest API for new builds.
• Dynadot. XML and JSON. Massive TLD coverage including obscure ccTLDs.
• Enom, OpenSRS, Tucows. Wholesale-only via reseller programs. Heavy onboarding.

Picking one

Three trade-offs:

1. TLD coverage. If you need to offer .fr, .de, .cn, you need a registrar with local-presence options. Most boutique registrars don't have them.
2. Margin. Wholesale price vs your retail price. Big registrars (Enom, Namecheap reseller) have better margins; small ones (Porkbun) have thinner.
3. Onboarding friction. Cloudflare and Porkbun: sign up, get an API key, go. Enom and Tucows: contracts, paperwork, deposits, weeks of back-and-forth.

For an MVP, integrate Namecheap or Porkbun. Add a second registrar (for TLD coverage and failover) only after the first generates revenue worth the work.

In a custom-domain SaaS

A domain API is the back end of a "buy a domain in our app" flow. Separate from DNS management. After registration:

• Set the domain's nameservers to your DNS service (or the customer's preferred DNS host).
• Trigger the DNS template application to add records pointing at your platform.
• Hand off to your DNS API for ongoing record changes.

If your platform offers domain registration, build the registrar abstraction (interface, multiple implementations) from day one. Customer domain workflows benefit from being registrar-agnostic later.