Bulk domain check in Python: availability, expiry dates and registrar for a whole list

#automation #python #tutorial #webscraping

If you keep a portfolio of domains, watch competitors' domains, or want to know which names on a shortlist are still free, checking them one by one in a WHOIS web form does not scale. Command-line whois output is free text that differs per registry, so parsing it is its own project. A cleaner route is RDAP, the JSON successor to WHOIS that registries publish, combined with a few DNS queries.

This post shows how to run that for a list of domains with an Apify actor I built, Bulk Domain WHOIS (RDAP) and DNS Lookup, and then triage the results in Python. Disclosure: it's my actor and I earn a little when it's used. It only wraps public RDAP and DNS, so you could also build it yourself.

Price

Pay-per-event: $0.002 per domain looked up at the time of writing (so $2 per 1,000). Errors, invalid names and unknown results are not charged. Duplicates in your list are removed. Max 1000 domains per run.

Input

{
  "domains": ["github.com", "python.org", "stripe.com", "expired-example-zzqx-48213.com", "notadomain", "https://www.wikipedia.org/page"],
  "maxConcurrency": 10
}

URLs are accepted and reduced to the host name (see wikipedia.org below).

Real output

I ran the actor's source locally on exactly that input on 2026-10-16. Three of the six rows, trimmed (the full output also has a txt field and a checkedAt timestamp):

[
  {
    "domain": "stripe.com",
    "available": false,
    "registrar": "SafeNames Ltd.",
    "created": "1995-09-12T04:00:00Z",
    "expires": "2027-09-11T04:00:00Z",
    "ageDays": 11357,
    "status": ["client delete prohibited", "client transfer prohibited", "..."],
    "nameservers": ["ns-1087.awsdns-07.org", "ns-1882.awsdns-43.co.uk", "..."],
    "a": ["198.137.150.231", "198.202.176.231"],
    "mx": ["10 aspmx.l.google.com", "20 alt1.aspmx.l.google.com", "..."],
    "source": "rdap"
  },
  {
    "domain": "expired-example-zzqx-48213.com",
    "available": true,
    "registrar": null,
    "created": null,
    "expires": null,
    "ageDays": null,
    "status": [],
    "nameservers": [],
    "a": [],
    "mx": [],
    "source": "rdap"
  },
  {
    "domain": "notadomain",
    "available": null,
    "error": "Not a valid domain name"
  }
]

So: a registered domain has registrar, created, expires, ageDays, nameservers, mx. An unregistered one has available: true and empty fields. An invalid name has an error and available: null. mx entries are "priority host" strings.

Caveat: available: true means the registry returned no record for the name. It is a good first filter, not a guarantee you can buy it (premium or reserved names exist), so confirm at a registrar before relying on it.

Call it from code

from apify_client import ApifyClient

client = ApifyClient("YOUR_APIFY_TOKEN")
run = client.actor("pennydata/bulk-domain-whois-dns-lookup").call(
    run_input={"domains": ["github.com", "python.org", "stripe.com"], "maxConcurrency": 10}
)
rows = client.dataset(run["defaultDatasetId"]).list_items().items

Triage: free names, soon-to-expire domains, errors

This function reads only fields that appear in the output above. I ran it on the saved dataset from that run:

from datetime import datetime, timezone

def triage(rows, days=365):
    now = datetime.now(timezone.utc)
    free, expiring, errors = [], [], []
    for r in rows:
        if r.get("error"):
            errors.append((r["domain"], r["error"]))
        elif r["available"]:
            free.append(r["domain"])
        elif r["expires"]:
            exp = datetime.fromisoformat(r["expires"].replace("Z", "+00:00"))
            left = (exp - now).days
            if left <= days:
                expiring.append((r["domain"], left, r["registrar"]))
    return free, sorted(expiring, key=lambda t: t[1]), errors

free, expiring, errors = triage(rows, days=700)

On 2026-10-16 with days=700 it returned:

free:     ['expired-example-zzqx-48213.com']
expiring: [('wikipedia.org', 88, 'MarkMonitor Inc.'), ('stripe.com', 329, 'SafeNames Ltd.')]
errors:   [('notadomain', 'Not a valid domain name')]

(The day counts depend on the date you run it. A domain showing 88 days left may well be auto-renewed; expires is the registry's date, not a promise it will lapse.)

Notes and limits

Data comes from the registry's RDAP server, so which fields exist (and whether registrar names are redacted) varies by TLD. Don't assume every TLD fills every field.
I tested six domains, all .com or .org. I did not test large batches or rarer TLDs for this post, so check a sample of your own list first.
To monitor a portfolio, schedule the actor on Apify and diff expires and nameservers between runs.

Written with AI (Claude).

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