MX record: Mail Exchanger record
An MX record is a DNS entry that names the servers which accept email for a domain, each with a priority number.
How it works
A sending server looks up the MX records for the part after the @ and tries the lowest priority number first. If a domain has none, senders fall back to the domain's address record, and a domain can publish a "null MX" to say it accepts no mail at all.
A domain with no working way to receive mail cannot have a real mailbox, which is why an MX lookup is the cheapest useful check on an email address.
Related LookValid products
| Product | Credits | Docs |
|---|---|---|
| Email Domain Check | 1 credit per address checked | API docs |
New to the API? Start with the quickstart or the API reference. Agents can call the same lookups through the MCP server.