Free tools
15 checks that run on the same engine as our API. No signup, no daily limit, and nothing you check is stored. They are free because they answer from numbering plans, public DNS and bundled reference data, which costs us nothing to serve.
Syntax, DNS, deliverability signals and the catch-all problem behind most false positives.
Free email address validator
Check syntax, DNS, MX records and deliverability signals for any email address. Free, no signup.
Disposable email address checker
Check whether an email address uses a throwaway or temporary inbox provider. Free, no signup.
Catch-all domain checker
Find out whether a domain accepts mail for every address - the reason email validators report false positives. Free.
Role account checker
Check whether an email address is a shared role mailbox like info@ or support@ rather than a person. Free.
Email typo checker and fixer
Catch misspelled email domains like gmial.com and get the correction. Free, no signup.
Phone
Numbering plans, regulator allocations and line types. All offline, all free.
Free phone number validator
Check whether a phone number is valid in its country numbering plan. Free, no signup, 200+ countries.
Reserved and fake phone number checker
Check whether a phone number sits in a regulator-reserved block that can never be allocated. Ofcom, ACMA, NANPA and more.
VoIP or mobile? Line type checker
Check whether a US phone number is likely VoIP rather than a real mobile. Free. The check cheap APIs get wrong 1 in 4 times.
E.164 phone number formatter
Convert any phone number into E.164 international format. Free, no signup, 200+ countries.
Domain & DNS
Live DNS queries for mail routing and anti-spoofing configuration.
MX record lookup
Look up the MX records for any domain and see who handles its mail. Free, live DNS query, no signup.
SPF record checker
Check a domain SPF record for syntax problems, soft-fail settings and the 10-lookup limit. Free.
DMARC record checker
Check a domain DMARC policy, alignment and reporting setup. Free live DNS lookup, no signup.
IP address
Range classification and network attribution, without a geolocation licence.
IP address checker
Check whether an IP address is public, private, reserved or carrier-grade NAT. Free, no signup, IPv4 and IPv6.
Datacenter IP checker
Check whether an IP belongs to a hosting provider such as AWS, Google Cloud or Hetzner rather than a home connection. Free.
Carrier-grade NAT (CGNAT) checker
Check whether an IP sits in the 100.64.0.0/10 carrier-grade NAT range shared between mobile subscribers. Free.
Where the free tools stop
Everything here is decidable offline or from public DNS: numbering plans, regulator allocations, MX records, SPF and DMARC, IP range tables. That covers a surprising amount of real-world bad data — misspelled domains, numbers that were never allocated, domains that publish an explicit refusal to accept mail.
What it cannot answer is whether a specific mailbox exists or whether a line is switched on right now. Those need a live conversation with a mail server or a carrier, which is what the paid API does — and where most of the industry quietly guesses instead.