MX Lookup
Type a domain, or a whole email address, to see its MX records: the servers that accept its email, each with a priority number, and the lowest number is tried first. The lookup names the provider behind them, so stripe.com's aspmx.l.google.com reads as Google Workspace and microsoft.com's microsoft-com.mail.protection.outlook.com as Microsoft 365. No MX record at all means senders fall back to the domain's A record; a single MX of "." (a null MX) means the domain says it accepts no email.
Free, no sign-in, 20 lookups a minute. Answers are cached for 5 minutes. Also: DNS lookup, Nameserver lookup, TXT record lookup.
Who handles well-known domains' email
Looked up on November 4, 2026 through Cloudflare's resolver, the same one this tool asks. Click a domain to run it live.
| Domain | Provider | First mail server | MX |
|---|---|---|---|
| gmail.com | Google Workspace (Gmail) | 5 gmail-smtp-in.l.google.com | 5 |
| stripe.com | Google Workspace (Gmail) | 10 aspmx.l.google.com | 5 |
| microsoft.com | Microsoft 365 (Exchange Online) | 10 microsoft-com.mail.protection.outlook.com | 1 |
| proton.me | Proton Mail | 10 mail.protonmail.ch | 2 |
| fastmail.com | Fastmail | 10 in1-smtp.messagingengine.com | 2 |
gmail.com's five servers run from priority 5 to 40, so the first is tried before the four alternates. Stripe runs its mail on Google Workspace.
MX Lookup questions
What does the MX priority number mean?
Lower is tried first; the number itself means nothing else. gmail.com publishes 5 MX records at priorities 5, 10, 20, 30 and 40, so senders try gmail-smtp-in.l.google.com first and the alt1 to alt4 servers only if it does not answer. Records with the same priority share the load: senders pick among them at random.
How do I find out which email provider a company uses?
Look up its MX records: the host names give the provider away. On 4 November 2026 stripe.com's pointed to Google Workspace, microsoft.com's to Microsoft 365, proton.me's to mail.protonmail.ch and fastmail.com's to messagingengine.com. When the MX is a filtering service such as Proofpoint or Mimecast, the mailbox provider sits behind it: the SPF record in the TXT record lookup usually names it (include:spf.protection.outlook.com means Microsoft 365, include:_spf.google.com Google).
Can a domain receive email without an MX record?
Often, yes. When a domain has no MX record, mail servers fall back to delivering to its A or AAAA address (the implicit MX of RFC 5321), so a domain whose web server also runs mail can still get it. To say a domain takes no email at all, publish a null MX, one record of 0 . (RFC 7505), and senders bounce at once instead of retrying for days.
Can an MX record point to an IP address?
No. An MX record names a host, and that host must have its own A or AAAA record; an IP address in the MX field is invalid, and the host may not be a CNAME either (RFC 2181). If your DNS host asks for a mail server, give it a name like mail.example.com and create an A record for that name.
More free domain tools
The DNS lookup shows every record a domain publishes. The Nameserver lookup shows a domain's nameservers and which company hosts its DNS. The TXT record lookup reads a domain's SPF and DMARC records. For who registered a name and when, use the WHOIS lookup, Domain age checker or Domain expiration checker. See which extensions a name is still free in with the domain availability checker, or price one in the domain value calculator.