Every signal about a domain, in one REST call.

WHOIS, DNS, SSL, subdomains and email security for any domain, returned as clean JSON.

1,000 requests a month freeNo credit cardMIT-licensed source
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What one call returns

Call /lookup for everything, or one endpoint at a time. Same key and price for all of them.

All five signals

Everything below, fetched in parallel. Add ?wait=1 to wait for every subdomain source to finish.

GET/lookup/{domain}

WHOIS / RDAP

Registrar, registration and expiry dates, nameservers, status. RDAP first, then port-43 WHOIS for 50+ TLDs.

GET/domain/{d}/whois

DNS records

A, AAAA, MX, TXT, NS, CAA and SOA, resolved in parallel.

GET/domain/{d}/dns

SSL certificate

Live TLS handshake: issuer, subject, validity dates, days until expiry, SANs.

GET/domain/{d}/ssl

Subdomains

Live hosts with their IPs, kept apart from historical names. From CT logs, passive DNS (25+ sources) and brute-force.

GET/domain/{d}/subdomains

Email security

SPF and DMARC records, plus DKIM keys found on 29 common selectors.

GET/domain/{d}/email-security

Results are cached: DNS 5 min, WHOIS 1 h, SSL 6 h, subdomains 24 h, email security 1 h.

Pricing

Every plan includes all endpoints. Billed monthly through RapidAPI. Cancel anytime.

BASIC
$0 /mo
Try the API and run small projects.
  • 1,000 requests / month
  • All endpoints
  • No credit card
Best for production
PRO
$9.99 /mo
Production apps with steady volume.
  • 50,000 requests / month
  • $0.0002 per request
  • Overage $0.0005 / request
  • Email support
ULTRA
$39.99 /mo
Domain features inside a SaaS product.
  • 500,000 requests / month
  • $0.00008 per request
  • 60% cheaper per request than PRO
  • Overage $0.0002 / request
  • Email support
MEGA
$149.99 /mo
Data platforms and high-volume scanning.
  • 5,000,000 requests / month
  • $0.00003 per request
  • 85% cheaper per request than PRO
  • Overage $0.0001 / request
  • Dedicated support channel
Get free API key Start on BASIC and upgrade on RapidAPI when you need more.

Requests over the monthly quota are billed at the overage rate. Cached responses count like fresh ones.

Compare with DomainTools, WhoisXMLAPI and Sublist3r
OTI LabsDomainToolsWhoisXMLAPISublist3r (open source)
Free tier1,000 requests/mo, no cardNoneLimited trialFree, self-hosted
Starting paid plan$9.99/mo$99/mo~$49/mon/a
WHOIS / RDAPRDAP with port-43 WHOIS fallbackWHOISWHOIS + RDAP—
DNS, SSL, subdomains and email in one callYesSeparate productsSeparate endpointsSubdomains only
SubdomainsCT logs, passive DNS (25+ sources), brute-force; live hosts with IPsPassive DNSSeparate APIPassive sources + brute-force
SetupMinutes (RapidAPI key)Sales callAccount + verificationInstall and run yourself
Hosted and cachedYesYesYesNo
Source codeMIT on GitHubNoNoYes

From public pricing pages, May 2026. Check each vendor for current plans.

What people build with it

Security and threat intel

Enrich indicators, check new look-alike domains, review certificates and DNS during an incident.

Attack surface monitoring

Track live subdomains, their IPs and new certificates for domains you own.

Lead enrichment

Mail provider from MX, domain age, DMARC posture and subdomain footprint before a lead enters your CRM.

Email deliverability

Check SPF, DMARC and DKIM before you send.

Registrar and hosting dashboards

Show live SSL, DNS and WHOIS status without running your own scrapers.

SaaS custom domains

Validate DNS and SSL when a customer connects a domain.

Free tools, no signup

Report for any domain

Everything the API returns, as a web page.

Enter a valid domain, like example.com

Reports directory

Over 230 domains, grouped by category.

Browse reports

Change alerts BETA

Daily checks and an email when a domain's certificate, subdomains, DNS, WHOIS or email records change. Free for one domain. Start from any report page.

Open a report

Open source

Built and run in production by Osiris Technical Institute. The API source is MIT-licensed.

View on GitHub