Checking domain availability, WHOIS and DNS from one API call

DomSDK — Fri, 13 Nov 2026 06:09:43 +0000

If you've ever built a domain search box, a brand-name generator or an internal "is this domain still ours?" check, you know the pattern: one provider for availability, another for WHOIS/RDAP, a DNS resolver library, and maybe an SSL checker on top. Each has its own auth, its own JSON shape and its own rate limits.

I've been trying out DomSDK, a domain data API that puts these lookups behind a single key and a consistent JSON style. Here's a quick walkthrough of the calls I found most useful.

1. Availability

curl "https://api.domsdk.com/v1/availability?domain=my-new-idea.com" \
  -H "Authorization: Bearer YOUR_KEY"

The response is a small object with the domain, the TLD and an available boolean, which is all a search box really needs.

2. WHOIS / RDAP

curl "https://api.domsdk.com/v1/whois?domain=example.com" \
  -H "Authorization: Bearer YOUR_KEY"

You get the registrar, the created and expiry dates and the nameservers. That's handy for expiry reminders on a portfolio of domains.

3. DNS records

curl "https://api.domsdk.com/v1/dns?domain=example.com&type=NS" \
  -H "Authorization: Bearer YOUR_KEY"

Swap type for MX, A, TXT and so on. It's useful for checking that a migration actually propagated.

4. SSL certificate

curl "https://api.domsdk.com/v1/ssl?domain=example.com" \
  -H "Authorization: Bearer YOUR_KEY"

This returns validity, issuer and expiry, which is enough for a simple "certificate expires soon" alert.

Putting it together

A tiny script that checks a list of candidate names and prints the free ones:

import requests

KEY = "YOUR_KEY"
names = ["brightledger.com", "quietforge.io", "example.com"]

for name in names:
    r = requests.get(
        "https://api.domsdk.com/v1/availability",
        params={"domain": name},
        headers={"Authorization": f"Bearer {KEY}"},
        timeout=10,
    )
    data = r.json()
    print(name, "available" if data.get("available") else "taken")

Notes

The free tier is 1,000 credits a month with no card, which covers a lot of side-project lookups.
It also exposes an MCP server, so AI coding agents can run the same lookups as tools.
DomSDK is an independent service and isn't affiliated with DomScan or other similarly named tools.

If you're juggling several domain-data providers in one project, it's worth a look: domsdk.com.