lookupdock

Free tool

MX lookup and email domain checker.

Inspect a domain's mail-routing records and what they mean. No account required, and no email is sent.

Check a domain

No account or credits required.

Enter a domain only, without an email address or URL. Use the ASCII/punycode spelling for internationalized domains.
Clear result

The domain is sent to LookupDock and its DNS resolver for this result. It is not saved to lookup history or sent to analytics or a mailbox-verification supplier.

Your result

Enter a domain to see its MX records, priorities and domain-level signals here.

Mailbox existence, inbox placement, catch-all behavior and deliverability are not checked.

What an MX lookup tells you

An MX record names a domain's mail exchanger and its priority. When no MX is published, mail systems can use the domain's A or AAAA records as an implicit fallback. A null MX explicitly declares no email service. A failed DNS request leaves the answer unknown.

For example, 10 mail.example.com. names a mail exchanger; 0 . declares no mail service. These are illustrative records, not live results for example.com. To inspect records yourself, run dig MX example.com or nslookup -type=MX example.com.

DNS records do not prove that an individual inbox exists, accepts your message or has consented to contact. This tool makes DNS queries only; it does not open a connection to the domain's website or mail server.

Why can two MX tools disagree?

Tools can ask different resolvers, use cached answers, check different domain names or encounter temporary failures. After a DNS change, compare the query name and returned TTL as well as the records. A failed lookup is different from a successful answer with no MX records.

Technical references: SMTP address resolution (RFC 5321 §5.1) and null MX (RFC 7505). Interpretation reviewed 6 November 2026.

Domain lists: disposable-email-domains (CC0; core) and disposable/disposable-email-domains (MIT; wider review list). Downloaded lists supersede the bundled snapshots. Lists can contain stale entries and miss new domains.

Check domains in a recurring workflow

Use the email API for syntax, mail-domain and disposable-address signals, or review a lead list through CSV. The current API's mx_found also includes address-record fallback; it is not an export of this tool's explicit MX-record table.

Automate email checksClean a CSV

Apply disposable-email signals to signups · See pricing

API and CSV: 7-day trial with 500 credits, card required. Then $99/month for 20,000 shared credits.