How do I find out who my email provider is?

Enter the part of your address after the @ above. If it's a personal address like gmail.com or outlook.com, the provider is in the name; for a work or custom domain, the MX records show which company actually hosts the mailboxes.

How can I tell if a company uses Google Workspace or Microsoft 365?

If the MX hosts end in google.com or smtp.goog, it's Google Workspace. If they end in mail.protection.outlook.com, it's Microsoft 365. If the MX points at a gateway such as Proofpoint, check SPF: include:spf.protection.outlook.com points to Microsoft 365 and include:_spf.google.com to Google.

Is the company that hosts my DNS the same as my email host?

Not necessarily. DNS can be hosted by your registrar or Cloudflare while email is hosted by Google or Microsoft. The DNS host is shown by the domain's NS records (dig NS acme.com); this tool reads MX and SPF, which show the email host.

What does it mean if the MX record is Proofpoint or Mimecast?

The company filters inbound mail through that security gateway before it reaches the mailboxes. The mailbox provider is behind it, and the SPF record is the usual clue to which one.

What if the domain has no MX record?

The tool says so. Under RFC 5321, senders then fall back to the domain's own address record, which rarely runs a mail server, so mail will probably fail. A null MX record goes further: it says the domain accepts no mail at all.

Can I look up an email address instead of a domain?

Yes. Enter the full address and the part after the @ is looked up. The tool doesn't check whether that mailbox exists; it only reads the domain's DNS records.

Is there a free email provider lookup with no sign-up?

Yes, this one. Ten lookups a minute from one connection, to keep the tool fast for everyone. Each lookup is two DNS queries and nothing is stored.

Email provider lookup: who hosts email for a domain

An email provider lookup tells you which company hosts a domain's mailboxes, such as Google Workspace, Microsoft 365 or Zoho. Enter a domain or email address and press Find the provider: the tool reads the domain's MX records, which name the servers that receive its mail (aspmx.l.google.com is Google Workspace, *.mail.protection.outlook.com is Microsoft 365). If a security gateway such as Proofpoint or Mimecast sits in front, it reads SPF for the most likely provider behind it.

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SimpleAPI

Sample result

Google Workspace runs email for acme.example.

Mail provider: Google Workspace
Domain: acme.example
Lowest MX: aspmx.l.google.com

What this means for you

Know the provider before you write, so you can match their sending rules and spam filters.

Next step:Check an address there is real

Names the provider behind each MX host
Spots security gateways in front of the inbox
Reads SPF includes for the real mailbox host
Accepts a domain or a full email address

By SimpleVerifier Team · Last updated October 19, 2026

Run 120 times this week

How to look up a domain's email provider

Enter a domain (acme.com), an email address or a website URL.
Press Find the provider. The tool queries the domain's MX and SPF records.
Read the headline: the mailbox provider, a gateway in front of it, a forwarding service, or no mail at all.
Check the MX table for the raw hosts and priorities, and the SPF line for the services allowed to send as the domain.

Example

You enter: The domain acme.example, or any address at it such as sales@acme.example.
You get: Google Workspace, labelled Mailbox host: its MX records are aspmx.l.google.com (priority 1) and alt1.aspmx.l.google.com (priority 5), and SPF includes _spf.google.com. Behind a gateway such as Proofpoint, the provider named in SPF is shown as the likely mailbox host.
Limits: One domain per lookup and 10 lookups a minute per connection. No account needed.

How do I find out who hosts email for a domain?

Look up the domain's MX records: providers name their mail servers after themselves. Every domain that receives email publishes MX records that point at mail servers. Google Workspace hosts end in google.com or smtp.goog (Google's MX values); Microsoft 365 hosts end in mail.protection.outlook.com (Microsoft's DNS records); Zoho's end in zoho.com. The tool matches the MX host with the lowest preference number, the one senders try first under RFC 5321, against the rules in our study of email providers at large companies, which cover about 40 mailbox providers, gateways and forwarding services.

Nothing is sent to the domain's mail servers. The lookup is two DNS queries, MX and TXT, the same data you'd get from dig MX acme.com and dig TXT acme.com. For the raw records without the naming, use the MX lookup.

Why does the MX record show Proofpoint or Mimecast instead of the provider?

Because the company filters inbound mail through a security gateway before it reaches the mailboxes. Many companies, large ones especially, route mail through Proofpoint, Mimecast, Cisco Secure Email, Barracuda or similar first. Then the MX record names the gateway, not the mailbox provider. In our study of S&P 500 domains, over half routed mail through a gateway first.

The SPF record usually fills the gap. It lists the services allowed to send as the domain, and a company whose staff send from Microsoft 365 has to include spf.protection.outlook.com; one on Google Workspace includes _spf.google.com. That's strong evidence, not proof: a domain can include Microsoft for one application while hosting mailboxes elsewhere, so the tool says "most likely".

Why does the email provider matter for verification and outreach?

It shapes how far you can trust a mailbox check. Domains behind a security gateway such as Proofpoint, Mimecast or Barracuda are often catch-all: the gateway answers yes to any recipient before the real mailbox server is ever asked, so a mailbox check there can't confirm the address. Verifying emails behind security gateways covers what to do about it.

For outreach, the split tells you which filters you're writing for, and helps when segmenting a list by mailbox provider. For IT work it's a quick way to confirm a migration has finished: once MX points at the new provider, new mail goes there. For a whole list of domains at once, use the bulk email provider lookup.

Is this easier than reading MX records with dig?

	This tool	`dig MX` and `dig TXT`
Raw MX hosts and priorities	Shown	Shown
Provider named	Yes, for about 40 providers	You read the hostnames
Provider behind a gateway	Inferred from SPF	You read the SPF includes
Works without a terminal	Yes	No

From a terminal: dig +short MX acme.com and dig +short TXT acme.com | grep spf.

Who uses this tool, and for what?

Cold emailers: See whether a target company is on Google Workspace, Microsoft 365 or behind a gateway before you write the sequence, and expect catch-all results from gateway domains when you verify.
Sales ops: Find out what a prospect runs on before a sales call, or tag accounts by provider for routing. For a whole account list, use the bulk lookup.
IT admins: Confirm a migration to Google Workspace or Microsoft 365 is live by checking MX now points at the new provider, and spot leftover SPF includes from the old one.
Agencies: Check a new client's mail setup in one step before touching their DNS, then check SPF, DKIM and DMARC with the SPF checker.

What can’t this tool tell you?

Behind a gateway, the provider is a best guess from SPF, not proof. One SPF include can be for a single app rather than the staff mailboxes.
Hosts outside our list of about 40 providers are shown as raw MX hosts without a name.
It reads the domain's records, not a mailbox. It can't tell you whether a given address exists.
Resellers can hide the provider: secureserver.net is GoDaddy, which may be selling Microsoft 365 or its own mail.

Common questions

How do I find out who hosts email for a domain?: Look up the domain's MX records; the hostnames name the provider. Enter the domain above and the lookup does it for you, naming Google Workspace, Microsoft 365, Zoho and others, plus any security gateway in front of them.
How do I find out who my email provider is?: Enter the part of your address after the @ above. If it's a personal address like gmail.com or outlook.com, the provider is in the name; for a work or custom domain, the MX records show which company actually hosts the mailboxes.
How can I tell if a company uses Google Workspace or Microsoft 365?: If the MX hosts end in google.com or smtp.goog, it's Google Workspace. If they end in mail.protection.outlook.com, it's Microsoft 365. If the MX points at a gateway such as Proofpoint, check SPF: include:spf.protection.outlook.com points to Microsoft 365 and include:_spf.google.com to Google.
Is the company that hosts my DNS the same as my email host?: Not necessarily. DNS can be hosted by your registrar or Cloudflare while email is hosted by Google or Microsoft. The DNS host is shown by the domain's NS records (dig NS acme.com); this tool reads MX and SPF, which show the email host.
What does it mean if the MX record is Proofpoint or Mimecast?: The company filters inbound mail through that security gateway before it reaches the mailboxes. The mailbox provider is behind it, and the SPF record is the usual clue to which one.
What if the domain has no MX record?: The tool says so. Under RFC 5321, senders then fall back to the domain's own address record, which rarely runs a mail server, so mail will probably fail. A null MX record goes further: it says the domain accepts no mail at all.
Can I look up an email address instead of a domain?: Yes. Enter the full address and the part after the @ is looked up. The tool doesn't check whether that mailbox exists; it only reads the domain's DNS records.
Is there a free email provider lookup with no sign-up?: Yes, this one. Ten lookups a minute from one connection, to keep the tool fast for everyone. Each lookup is two DNS queries and nothing is stored.

Sources

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