Test-send sample picker: pick a first batch with a few addresses of every mailbox type
In short: Choose the sample size and the tool picks rows round-robin across Gmail, Microsoft, Yahoo, iCloud, Proton, other personal mailboxes and company domains. Limit: Mailbox types come from the domain name only, not from where the mail is hosted.
Upload a CSV or .xlsx file, or paste it with a header row. Pick the email column and the size of the sample. The tool sorts the addresses into mailbox types from the domain after the @, then picks one from each type in turn until the sample is full. The pick is repeatable: the same list and seed give the same rows.
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. Check your list free nowSee pricing
Sample result
Ten example rows give a sample of 5 with one address from each of 5 groups: Gmail, Microsoft, Yahoo, iCloud and company domains.
- Rows in the sample
- 5
- Not addresses
- 0
- Repeats skipped
- 0
What this means for you
A sample shows how those addresses behave, not the rest; a check shows which addresses exist.
- Round-robin across types
- Group limit optional
- Repeatable seed
- Types from the domain
- Sample
- Mailbox type
- CSV
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
Sample picked? Check it before the first batch goes out.
- Download the sample, or use the check button under the result, which carries its addresses across.
- Upload or paste it at /verify. Every address gets a live mailbox check, and the first 100 email checks are free with a Google sign-in, no card.
How do I pick a mixed test batch from a list?
- Upload the file as a CSV or .xlsx, or paste the cells with the header row first.
- Pick the email column and the number of rows you want in the first batch.
- Choose to spread across mailbox types or across every domain, and optionally cap each group.
- Check the table of groups and download the sample.
Example
- You enter
- Ten rows with ava, ben and cara at gmail.com, dev at outlook.com, eli at hotmail.com, fay at yahoo.com, gus and hana at acme.com, ivo at globex.de and jun at icloud.com, with a sample of 5 spread across mailbox types and seed 1.
- You get
- 5 rows, one from each of 5 groups: Gmail (ava), Microsoft (dev), Yahoo (fay), iCloud (jun) and company domains (ivo). The same list and seed give the same rows.
- Limits
- Runs in your browser; nothing is uploaded. Types come from the domain name only, so a company address hosted at Google shows as a company domain.
Why not take the first rows of the file?
A list is often sorted by source, date or company, so its first rows are one kind of address. A first batch made of only company domains tells you nothing about how Gmail or Outlook treat you. Spreading the batch across mailbox types lets you watch bounces and replies by type before the rest goes out.
A small first batch is a way to look before you send the rest. It does not predict how the remaining addresses will do.
How are the types decided?
Only by the domain written after the @. Gmail and Googlemail are Gmail; Outlook, Hotmail, Live and MSN are Microsoft; Yahoo and its sister domains are Yahoo; AOL, iCloud (including me.com and mac.com) and Proton have their own groups; other known free mail domains are other personal mailboxes, and everything else is a company domain.
A company address hosted at Google Workspace or Microsoft 365 shows as a company domain, because only an MX lookup shows who hosts the mail. To split by host, use the ESP matching list splitter.
How is the sample filled?
Groups are ordered from the largest to the smallest. The tool takes one random address from each in turn, round and round, until the sample is full or the groups are empty. A group limit stops one group filling the sample, and a seed makes the random picks repeatable. Repeated addresses count once.
For a plain random sample with an estimate of the invalid rate, use the email list sampler.
Who uses this tool, and for what?
- Cold emailers
- Send the first 100 of a new list with every mailbox type in it and watch the bounces.
- Newsletter owners
- Pick a test group for a new template that includes the main mailbox types.
- Agencies
- Show a client a mixed sample of the list before the full campaign.
What can’t this tool tell you?
- Mailbox types come from the domain name only, not from where the mail is hosted.
- A sample shows what happened to those addresses and predicts nothing about the rest.
- A repeatable random pick is not a statistical sample of the whole list.
- Only the first sheet of a workbook is read.
Common questions
- Is the same sample picked every time?
- Yes. The same list, settings and seed always give the same rows. Change the seed for a different pick.
- What if a group has fewer rows than its turn needs?
- It simply runs out, and the other groups keep supplying rows until the sample is full or every group is empty.
- Can I spread by domain instead?
- Yes. Choose every domain on its own and each company domain becomes its own group, so a sample of 50 can touch 50 domains.
- Does a good first batch mean the rest will do well?
- No. It shows how those addresses behaved, nothing more. Check the whole list before the send.
- Are repeated addresses counted twice?
- No. Only the first row of an address can be picked, and the repeats are counted in the results.
- Is my file uploaded?
- No. The file is read in your browser and goes nowhere.
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.