Free APIs for every part
of the domain stack.
Public REST APIs for DNS, SSL, WHOIS, email auth, HTTP — no key, no signup. CORS-enabled so you can call them from browser JS. Rate-limited per IP at 30/min and 500/day. The same lookups behind Domainee's visual free tools, now scriptable.
18 APIs and counting.
DNS
7 APIsDNS Record Lookup API
Look up DNS records for any hostname. Returns all common record types (A, AAAA, CNAME, MX, TXT, NS, SOA) by default, or only the type you specify.
/v1/tools/dns-record-lookupCNAME Lookup & Generator API
Resolve a hostname's CNAME chain. Flags apex-domain misuse (apex domains can't legally have CNAME records per RFC 1034) and returns the full chain to the final A record.
/v1/tools/cname-lookupDNS Provider Lookup API
Fingerprint the DNS provider serving a domain from its public NS records. Returns the record name written the way that provider's form expects it (@ vs blank vs the full domain), whether it can point a zone apex, where its record editor lives, and the provider-specific settings that silently break custom domain setups.
/v1/tools/dns-provider-lookupDomain Connect Checker API
Check whether a domain's DNS provider implements the Domain Connect protocol, read live from the _domainconnect TXT record and the provider's settings endpoint. Reports the provider and whether it offers the synchronous flow (a signed redirect with no token exchanged, the one that works in practice) or only the asynchronous OAuth flow. One-click setup also needs the provider to have synced and enabled the service's template.
/v1/tools/domain-connect-checkerDNS Propagation Checker API
Query the same hostname against ~10 public resolvers across the world (Cloudflare, Google, Quad9, OpenDNS, etc.) and report which ones see the same answer. Useful right after a DNS change.
/v1/tools/dns-propagation-checkerReverse IP Lookup API
Resolve PTR (reverse DNS) records for an IP address, and list other domains observed on the same address. `hostnames` is the PTR answer, which is one or more names the IP's operator published; it is never a list of the sites hosted there, because DNS cannot produce one. `sharedHosts` is that separate list, from an observed-hostname corpus, and is null when no co-hosting source is configured. Private and reserved IPs are rejected.
/v1/tools/reverse-ip-lookupTXT Record Lookup API
Fetch all TXT records on a domain and classify them: SPF, DKIM, DMARC, BIMI, verification tokens (Google, Microsoft, Atlassian, etc.), or general.
/v1/tools/txt-record-lookupDomain
4 APIsWHOIS Lookup API
Modern RDAP-backed WHOIS lookup. Returns registrar, status, key dates (created/updated/expires), nameservers, and registrant info where public.
/v1/tools/whois-lookupDomain Age Checker API
RDAP-backed lookup that returns a domain's registration date, age in days + years, last-updated date, and expiration date.
/v1/tools/domain-age-checkerSubdomain Finder API
Enumerate subdomains for a target domain by querying Certificate Transparency logs (crt.sh) and DNS resolution. Returns deduplicated, sorted list.
/v1/tools/subdomain-finderDomain Availability Checker API
Check availability of a name across one or more TLDs. Uses DNS + RDAP fallback. Returns per-TLD availability with caveats (registrar lock, premium, etc.) where known.
/v1/tools/domain-availability-checkerSPF Record Checker API
Look up the SPF record for a domain, validate syntax, and count void/total DNS lookups against the RFC 7208 limit of 10. Flags common issues.
/v1/tools/spf-record-checkerDMARC Record Checker API
Look up the DMARC record at _dmarc.<domain>, parse the policy (`p`), subdomain policy (`sp`), alignment, reporting addresses (`rua`/`ruf`), and percentage. Flags issues like missing policy or too-permissive settings.
/v1/tools/dmarc-record-checkerDKIM Record Checker API
Look up the DKIM record at <selector>._domainkey.<domain>, parse the public key, key type (rsa/ed25519), and any issues. Validates against common provider conventions (Google `google`, Resend, Mailgun `mxvault`, etc.).
/v1/tools/dkim-record-checkerHTTP
3 APIsHTTP Header Checker API
Fetch a URL and return its response headers + a security grade based on HSTS, CSP, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, and Permissions-Policy presence.
/v1/tools/http-header-checkerRedirect Checker API
Follow a URL's redirect chain and return every hop with status code, response time, and the final destination URL. Stops at 20 hops to prevent loops.
/v1/tools/redirect-checkerWebsite Status Checker API
Issue a HEAD/GET to a URL and report whether it's up, the HTTP status, response time in ms, final URL after redirects, and basic SSL info.
/v1/tools/website-status-checkerHow these APIs work
- · Free, no API key. Just call the endpoint.
- · CORS-enabled. Call from browser JS, not just servers.
- · Standard JSON envelope:
{ ok, data }on success,{ ok, error: { code, message } }on failure. - · Per-IP rate limit: 30 requests/minute, 500/day. Returns HTTP 429 with
Retry-Afterheader when exceeded. - · Best-effort SLA. Free means free; for production-scale lookups, talk to us.
Build with the same APIs powering Domainee.
These free APIs are the foundation. The full Domainee platform adds custom-domain provisioning, SSL automation, MCP for AI agents, and a real free tier with 20 custom hostnames.