Domains-testnet

Use when naming a product, company or project and you need to know which domains are free: checks up to 10 domain names in one call against the authoritative registry RDAP servers (DNS delegation as fallback for TLDs without RDAP) and returns registered / available / likely-available / unknown per name, with expiry and registrar for taken ones.

Use when you need to check whether a domain is protected against email spoofing or set up for deliverability: reads MX (and guesses the mail provider), SPF (qualifier, lookup count), DMARC (policy, pct, report addresses), DKIM on common selectors, MTA-STS (record and policy mode), TLS-RPT and BIMI, and returns a grade A-F, a score and a list of concrete issues.

Use when you need to know whether a website or mail server has a valid HTTPS certificate or when it expires: opens a live TLS connection (SNI) to the host and returns whether the chain is publicly trusted (with the exact error, e.g. CERT_HAS_EXPIRED or self-signed), whether the certificate matches the hostname, validity dates and days remaining, subject, issuer, SAN list, key type, TLS protocol, cipher, ALPN and the certificate chain. Answers about the certificate even when it is invalid (that i

Use for attack-surface mapping, asset inventory or competitive research: lists every hostname under a domain that appears in unexpired publicly-logged TLS certificates, deduplicated, with wildcard flag, first-seen date, latest certificate expiry and issuer. Data from crt.sh (Sectigo) with Cert Spotter (SSLMate) as fallback; the response names the source. Only names in public certificates, no DNS brute force.

Use when you need to know who registered a domain through (registrar), when it was created, when it expires, its EPP status (e.g. clientTransferProhibited), nameservers and DNSSEC: queries the authoritative registry RDAP server (the modern WHOIS) found via the IANA bootstrap. Registrant personal data is never returned. Answers 404 (not charged) when the domain is not registered.

Use when you need the current DNS records of a domain or hostname: resolves the requested record types live over DNS-over-HTTPS (Cloudflare 1.1.1.1 with Google fallback) and returns every answer with TTL, plus the response code (NOERROR/NXDOMAIN) and whether DNSSEC validated. Up to 8 types per call.