Bulk MX lookup: which domains on my email list can receive mail?
In short: Paste addresses or domains and get each domain's MX hosts and provider, with domains that can't take mail (no MX, null MX, not registered) flagged and their addresses ready to copy. Limit: It reads DNS only; it doesn't connect to the mail servers or check any mailbox.
A bulk MX lookup reads the MX records of many domains at once. Paste email addresses or domains, up to 100 domains a run or 500 after a Google sign-in, and each domain gets its mail servers in priority order, the provider behind them, and a flag when it can't take mail: no MX, a null MX, or a domain that doesn't exist.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. See pricing
Sample result
acme.example has MX records. parked.example publishes a null MX, so it takes no mail.
- Domain
- parked.example
- MX
- 0 .
- Can receive mail
- No
What this means for you
Every address on a domain that can't take mail is a hard bounce. Drop them first.
- Emails or domains in
- MX hosts by priority
- Null MX and A-only flagged
- 100 domains a run, 500 signed in
- MX
- Bulk
- Dead domains
By SimpleVerifier Team · Last updated
Checking the domains of a whole list?
- Over 500 domains? Run them in batches of 500 when signed in and download the CSV after each.
- Remove the addresses on dead domains first: every one of them is a hard bounce.
- Then check the mailboxes on the domains that do take mail at /verify. The first 100 email checks are free with a Google sign-in, no card.
How do I check MX records for a list of domains?
- Paste email addresses, domains or a CSV export. Each address is cut down to its domain and repeats are looked up once.
- Press Look up MX records. Only the domains are sent for DNS lookups; the addresses stay in your browser.
- Read each domain's mail status, MX hosts with their priority, and the provider named from the first host.
- Copy the addresses on domains that can't receive mail, or download the CSV with every domain.
Example
- You enter
- Four addresses and a domain:
[email protected],[email protected],[email protected],[email protected]andumbrella.example. - You get
acme.exampleHas MX:mx1.acme.example(10),mx2.acme.example(20).globex.exampleHas MX on Google Workspace.initech.exampleNo MX, A record only.parked.exampleNull MX: takes no mail.umbrella.exampleDomain doesn't exist. Copy[email protected], the one address on a dead domain, or download the CSV.- Limits
- Up to 100 domains a run without an account and 500 when signed in with Google. DNS only; no mailbox is checked.
What does it mean when a domain has no MX record?
It usually means the domain doesn't receive email. A sending server looks up the MX records of the domain after the @ and delivers to the host with the lowest priority number (RFC 5321, section 5.1). With no MX, the same section lets it fall back to the domain's A or AAAA address as an implicit MX, so the tool marks those domains "No MX, A record only" rather than dead: mail may be tried there, but a website's server rarely runs a mailbox.
A domain with neither MX nor an address record, or one that doesn't exist at all (NXDOMAIN), can't receive mail. Every address on it is a hard bounce, which is why these are the cheapest rows to remove before a send.
What is a null MX record?
A null MX is a single MX record with priority 0 and the host ., defined in RFC 7505. It is a domain's explicit statement that it accepts no email, used on parked domains and on domains that only host a website. Senders should not try the A record fallback when they see it, so the tool treats null MX as "takes no mail". See the null MX glossary entry for how it is written in different DNS hosts.
How is this different from the bulk DNS lookup?
The bulk DNS lookup returns every record type you tick, for any host name. This tool asks only for MX and the address records needed to read the fallback, takes a list of email addresses as well as domains, and turns the answers into one verdict per domain plus the list of addresses to drop. To see who runs each domain's mail in more detail, use the bulk email provider lookup.
Is this faster than nslookup or dig?
| This tool | nslookup / dig | |
|---|---|---|
| Domains at once | 100, or 500 signed in | One per command |
| Takes email addresses | Yes, cut to the domain | No |
| Null MX and A fallback read | Yes, with a verdict | You read the raw answer |
| Addresses on dead domains | Listed to copy | No |
The command for one domain: dig +short MX example.com or nslookup -type=mx example.com.
Who uses this tool, and for what?
- Cold emailers
- Drop every lead on a domain with no mail server before the list goes into a sequence, so the first send doesn't open with hard bounces.
- Marketing teams
- Find old customer addresses on company domains that were sold, parked or closed.
- SaaS signups
- Spot signups made with domains that can't receive the confirmation email.
- IT and migrations
- Confirm which domains moved their MX to the new provider after a cut-over.
What can’t this tool tell you?
- It reads DNS only; it doesn't connect to the mail servers or check any mailbox.
- Answers come from a public resolver and can be cached for the record's TTL.
- Provider names come from known MX host patterns; unknown hosts show no provider.
- Up to 100 domains a run without an account and 500 signed in.
Common questions
- Does an MX record mean the email address exists?
- No. It means the domain accepts mail. Whether jane@ or sales@ is a real mailbox takes a mailbox check, which the free tool doesn't do; /verify does.
- What does MX priority mean?
- Senders try the host with the lowest number first and move to higher numbers if it doesn't answer (RFC 5321). Equal numbers share the load.
- Why does a big company's domain show no MX?
- Often the address uses a different domain from the website, such as a mail subdomain or a parent company domain. Check the exact domain after the @, not the website.
- Can I paste a CSV export?
- Yes. Every cell that looks like an address, URL or domain is cut to its domain, and repeats are looked up once.
- Why did a domain come back No answer?
- The DNS lookup timed out. That's not a missing record; run it again.
- Is the bulk MX lookup free?
- Yes, it's a free tool with no card: 100 domains a run, or 500 after a free Google sign-in.
Sources
A tidy list can still be full of dead addresses.
Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.
- Upload the cleaned file as it is: CSVs up to 100,000 rows
- A real SMTP mailbox check on every row, with catch-all detection
- Small list? Starter at $9/mo covers 2,500 emails a month, cancel anytime
Plans from $9 a month, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.