Domain Tools
77 free tools for DNS, email deliverability, DNS security, SSL/TLS, domain registration data and everyday developer tasks. No sign-up, no paid third-party APIs.
Domain Health Check
Enter any domain: 40+ checks across DNS, email authentication, SSL/TLS, DNS security and the website, scored out of 100 with plain-English fixes.
Tool sections
DNS Tools
Look up any record type, see every record at once, check propagation across public resolvers and nameserver consistency.
17 tools → 02Email & Deliverability
SPF, DKIM, DMARC, MX, reverse DNS, MTA-STS, TLS-RPT, BIMI and DANE - plus header and DMARC report analysers.
12 tools → 03DNS Security
DNSSEC, CAA, dangling CNAMEs, wildcard DNS, nameserver hardening and zone transfer tests.
8 tools → 04Website & SSL
Certificates, TLS versions, security headers, redirects, status, response time, HTTP/2 & HTTP/3, security.txt.
10 tools → 05Domain Information
RDAP registration data, age, expiry, status codes, availability, TLD information and subdomain discovery.
6 tools → 06IP & Network
IP address details, reverse DNS, host name lookup.
3 tools → 07Record Generators
Build correct SPF, DMARC, DKIM (with key pair), CAA, MTA-STS, TLS-RPT, BIMI and generic DNS records.
8 tools → 08Developer Tools
Subnet/CIDR calculators, IP conversions, URL/host parsers, Base64/URL encoding, JWT, timestamps, JSON, regex.
12 tools →Most used
DNS Security Audit
DNSSEC, CAA, nameservers, SPF, DKIM, DMARC, MTA-STS, TLS-RPT and BIMI in one security report.
Open tool →DNS Lookup
Look up any record type (A, AAAA, MX, TXT, NS, SOA, CAA, SRV, DNSKEY, DS, HTTPS/SVCB, TLSA and more).
Open tool →Full DNS Lookup
Every common record type on one page, including DMARC and common SRV records.
Open tool →DNS Propagation Checker
Compare the answer of 16 public resolvers with the domain's own nameservers.
Open tool →Email Authentication Checker
MX, SPF, DKIM, DMARC, reverse DNS, MTA-STS, TLS-RPT and BIMI scored out of 100.
Open tool →DNSSEC Checker
DS at the parent, DNSKEYs, DS↔key matching, signature validity and resolver validation.
Open tool →SSL/TLS Checker
Certificate issuer, expiry, SANs, chain, key, host name match, TLS versions and cipher.
Open tool →HTTP & Security Headers Checker
Every response header, graded: HSTS, CSP, X-Frame-Options, cookies, caching and more.
Open tool →WHOIS / RDAP Lookup
Registrar, dates, status codes (explained), nameservers and DNSSEC from the registry's RDAP server.
Open tool →IP Address Lookup
Address type/range, reverse DNS, notations and the network it belongs to.
Open tool →Every tool works without paid or keyed third-party APIs: DNS answers come from public DNS, registration data from each registry's own RDAP server, and website checks from a direct HTTPS request made by this site. Add &format=json to any lookup's address to get the result as JSON. Fair-use limits apply per visitor.