Free domain, DNS & SSL tools

Every lookup you reach for when wiring up domains — free, fast, and gate-free.

These are for the SaaS teams who get pulled into a customer's domain setup: a CNAME that won't resolve, a certificate that expired overnight, an SPF record that quietly broke email. Paste a hostname, get a straight answer — no account, no upsell wall between you and the result.

They aren't a grab-bag either. Every check here is one Approximated already runs continuously in production, against real customer domains: the same DNS resolution, TLS handshakes, RDAP queries, and redirect tracing that have kept millions of custom domains provisioned and renewing. The free tools just let you run one on demand.

DNS & email

DNS Record Lookup

Pull A, AAAA, MX, TXT, NS and CNAME records for any domain in a single query.

DNS Propagation Checker

Query five public resolvers at once to see whether a record has propagated everywhere yet.

CNAME Lookup

Follow a hostname's CNAME chain all the way to whatever it ultimately points at.

TXT Record Lookup

List every TXT record on a domain, sorted into SPF, DKIM, DMARC and verification buckets.

SPF Record Checker

Parse a domain's SPF record and count its DNS lookups against the limit of ten.

DMARC Record Checker

Read a domain's DMARC policy and see whether it actually enforces anything.

DKIM Record Checker

Fetch a DKIM selector's public key and confirm the key hasn't been revoked.

HTTP & TLS

SSL Certificate Checker

Inspect a host's live TLS certificate: expiry countdown, issuer, and SANs.

HTTP Header Checker

See the response headers a URL returns and grade its security headers A to F.

Redirect Checker

Trace every hop in a URL's redirect chain, all the way to the final destination.

Website Status Checker

Check whether a URL is up and how fast it responds, without following redirects.

Domains & IP

WHOIS Lookup

Look up a domain's registrar, key dates, nameservers and status via RDAP.

Domain Age Checker

Find a domain's registration date and exactly how many years old it is.

Domain Availability Checker

Check whether a domain is unregistered, or compare a name across several TLDs.

Reverse IP Lookup

Run a PTR lookup to find the hostnames that point back at an IP address.

These are the spot-checks. Approximated is what runs them for every customer domain, all the time.

Want to automate this?

Approximated automates custom domains end to end

DNS checks, SSL certificates, renewals, and routing for every customer domain — provisioned and monitored automatically, from 100 domains to millions.

Try it free