Check Any Domain in Milliseconds
Availability, WHOIS data, registrar info, and expiry dates — all from a single API call. No scraping, no rate limits on your end.
Trusted by teams at
What the Domain Checker API Does
One endpoint. Everything you need to know about a domain — availability, ownership, and registration history.
Accuracy
Every response includes parsed WHOIS data (domain ownership and registration records), DNS status (whether traffic-routing records exist), SSL validity (active HTTPS certificate), MX records (mail server configuration), and a reputation score — all normalized into a consistent JSON structure.
{
"domain": "example.com",
"available": false,
"dns": {
"a": ["93.184.216.34"],
"mx": ["mail.example.com"],
"ns": ["ns1.example.com"]
}
}
Simplicity
A single POST request with your API key is all it takes. No SDK, no configuration, no setup — just an HTTP call and a JSON response.
GET /v1/networking/domain/example.com
Host: requiems.xyz
requiems-api-key: YOUR_API_KEY
Built for Every Domain Workflow
From fraud prevention to onboarding — if it touches a domain name, this API has you covered.
Auth / Signup
Avoid risky domains before signup
Check domain health before accepting it as a user-provided business domain. Reject expired, parked, or flagged domains.
Fraud Prevention
Block malicious or expired domains
Detect domains flagged for spam or phishing, or those with lapsed registrations. Prevent bad actors from abusing your platform.
Integrations
Verify partner domains in workflows
Validate that partner or vendor domains are live and properly configured before integrating them into automated workflows.
Email Marketing
Inspect domain health before email campaigns
Check MX records and domain reputation before targeting an address list. Reduce bounce risk from entire sending domains.
DevOps / Monitoring
Detect missing DNS or SSL issues
Surface missing DNS records or expired SSL certificates before they cause downtime or user-facing errors.
Onboarding
Secure onboarding with trusted domains
Allow only domains with verified DNS, active MX, and clean reputation during business onboarding. Block throwaway or newly registered domains.
Pair It With Other APIs
Domain Checker is more powerful combined. Stack it with other Requiems APIs to build multi-point validation into a single workflow.
Domain Checker + Email Validator
Benefit: Validate both the domain and specific email address.
Outcome: Full email deliverability confidence: domain health plus mailbox-level checks.
Domain Checker + VPN Detection
Benefit: Check domain health while identifying VPN or proxy traffic from the same request.
Outcome: Double-layered fraud signal: a flagged domain combined with anonymized traffic is a strong block trigger.
Domain Checker + Phone Validator
Benefit: Verify domain health and phone number at the same onboarding step.
Outcome: Multi-point contact validation — confirmed digital presence and reachable phone — before granting access.
Frequently Asked Questions
Still have questions?
Contact supportAutomate this with Requiems.
One API key. Domain availability, WHOIS data, and 50+ other APIs across validation, networking, finance, and more.