Email list segmenter: split a list by domain, provider or country
Email list segmentation splits one list into smaller groups you can send to separately. Paste a list or upload a CSV above and this segmenter groups it by domain, mailbox provider (Gmail, Outlook.com, Yahoo, company domains), company versus free mail, or country code, then gives you one CSV per segment with your other columns kept.
Your other columns are kept in every segment file.
Sample result
4 rows split into 3 provider segments; company domains are the largest, with 2.
- Segments
- 3
- Largest
- Company domain (2)
- Rows
- 4
What this means for you
See how much of your list is company mail versus free webmail, and pace each group.
- Split by domain, provider, type or country
- One CSV per segment, or all in one file
- Every other column kept
- Company vs free webmail vs ISP mail
- Segments
- Providers
- CSV
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
How do I segment an email list?
- Paste addresses one per line, or upload a CSV; the email column is found automatically and the other columns stay with each row. Files can be up to 25 MB.
- Choose what to split by: domain, mailbox provider, company vs free vs ISP mail, or country-code top-level domain.
- Press Segment the list. Segments are listed largest first with their share of the list.
- Download any segment as its own CSV, or everything in one file with a segment column to import into your email platform.
Example
- You enter
- 4 addresses:
jane@acme.example,ana@acme.example,sam@gmail.comandleo@outlook.com, split by mailbox provider. - You get
- 3 segments, largest first: Company domain (2), Gmail (1) and Outlook.com (Microsoft) (1), each downloadable as its own CSV or as one file with a segment column.
- Limits
- No DNS lookups; providers are read from the domain. Runs in your browser with no row cap; an uploaded file can be up to 25 MB.
What is email list segmentation?
Email list segmentation is dividing a list into groups that share something, so each group gets the send, content or timing that suits it. Segments are often built from behaviour or profile data in an email platform; this tool builds them from the one thing every list has, the address itself.
The domain alone says a lot: whether the contact used a work or a personal address, which mailbox provider receives the mail, and often which country they're in. Those are the segments people most often need before importing a list or planning a send.
How do I split an email list by domain?
Choose Domain and run the list: every address is grouped by the part after the @, so all @acme.com contacts land in one segment, with a CSV for each. That's how B2B teams group contacts by account, or pull every address at one company before an account-based campaign.
For a ranked count of domains without splitting the file, the email to domain extractor is quicker. To split company addresses from Gmail and Outlook.com only, the business email checker does exactly that.
How do I segment emails by country?
Choose Country code. Addresses on country-code domains, such as .de, .fr or .co.uk, are grouped by that country, named from the two-letter code. Addresses on .com, .net, .org and other generic endings carry no country and are grouped by their ending instead.
Some country codes are sold as generic names, such as .io, .co, .me and .ai, so the tool labels them Used as generic rather than assigning a country. And a Gmail address says nothing about where its owner lives, so a country split is a partial answer at best.
Why is email list segmentation important?
Because sending each group what it signed up for keeps spam complaints down, and Google's sender guidelines set a spam-rate limit for bulk senders. Splitting by provider also matters on its own: Gmail, Yahoo and Microsoft each publish their own bulk sender requirements, and a segment per provider lets you pace a new domain's sends to each one separately.
See segmenting a list by mailbox provider for how to use provider segments when warming up or diagnosing a deliverability drop.
Segment here or in your email platform?
| This segmenter | Email platform segments | |
|---|---|---|
| Works on | Any list or CSV, before import | Contacts already in the platform |
| Splits by | Domain, provider, company vs free, country code | Fields, tags, behaviour, purchases |
| Output | A CSV per segment | A saved audience |
| Cost | Free, in your browser | Included in the platform's plan |
Who uses this tool, and for what?
- B2B marketers
- Group contacts by company domain for account-based campaigns, and split work addresses from personal ones before a product launch email.
- Cold emailers
- Split a lead list by mailbox provider to pace a new domain's sends to Gmail and Microsoft separately during warm-up.
- International teams
- Send a German-language version to .de, .at and .ch addresses and an English one to the rest.
- Agencies
- Show a client how their list breaks down by provider and company vs free mail before migrating platforms.
What can’t this tool tell you?
- Segments come from the domain alone. Which company hosts a company domain's mail takes an MX lookup; use the bulk MX lookup for that.
- Country is the country-code ending, not where the person is; generic endings and webmail say nothing about location.
- It doesn't check that addresses exist, so every segment still contains whatever bounces the list has.
- Up to the 100 largest segments are listed; the all-in-one download has every row.
Common questions
- What is email list segmentation?
- Dividing an email list into smaller groups that share a trait, such as domain, provider, location or behaviour, so each group can get its own message, timing or volume.
- What is email segmentation?
- The same thing: sending different emails, or the same email at different times or volumes, to different groups within a list instead of one blast to everyone.
- What is list segmentation in email marketing?
- Grouping subscribers by shared data, from signup source and purchase history to the address's domain, and targeting each group separately. This tool covers the address-based segments.
- What is email list management and segmentation?
- Keeping a list accurate (removing duplicates, bounces and unsubscribes) and dividing it into groups for targeted sends. Clean first, then segment, so dead addresses don't skew each segment.
- How to segment email lists?
- Decide the trait to split on, then group the list by it. For domain, provider or country, paste the list above; for behaviour or purchase data, use your email platform's segment builder.
- How to segment email lists in Mailchimp?
- Import the all-in-one CSV from this tool with its segment column mapped to an audience field, then build a segment in Mailchimp that filters on that field.
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? $9 one-time covers 2,500 emails, no subscription
One plan, 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.