Compare two email verifiers' results, row by row
In short: Matches two verifiers' results files by address, maps each status to valid, risky or invalid, and lists every row where they disagree with the likely reason: catch-all policy, unknown answers, role flags or a real conflict. Limit: It shows where two files disagree, not which one is right. Settle disputed rows with a recheck or a small test send.
Drop the results file from each verifier. Every address in both files is matched, each vendor's status is mapped to valid, risky or invalid, and you get the agreement rate, a 3x3 matrix and every disagreement with the likely reason. Most gaps come from catch-all domains: one tool calls them valid, the other risky. It runs in your browser, so nothing is uploaded.
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
Works with exports from ZeroBounce, NeverBounce, MillionVerifier, Bouncer, Kickbox, Emailable, Instantly, Clay, SimpleVerifier and others. Runs in your browser. Nothing is uploaded.
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
How do I compare two email verifiers on the same list?
- Verify the same list with both tools, on the same day if you can. Answers drift as mailboxes close and greylisting clears.
- Download the full results file from each one, including the column that holds the status (valid, invalid, catch-all and so on).
- Drop one file in A and the other in B. The email column and the status column are found from the values; sub-status, reason and accept-all columns are read when present.
- Press Compare results. Read the agreement rate, then the matrix: the off-diagonal cells are the disagreements.
- Read Why they differ, download
disagreements.csv, and recheck the disputed addresses or test them with a small send.
Example
- You enter
- Two results files for the same 10 addresses: one with
statusandsub_statuscolumns, the other withResult,ReasonandAccept All. - You get
- They agree on 4 of 10 (40%). Of the 6 disagreements, file A gave the more positive answer on all 6: one catch-all domain, one role address, one unknown, one disposable, one accepted vs rejected and one unknown vs no mail server.
- Limits
- Runs in your browser; each file can be up to 25 MB. It shows where the files disagree, not which one is right.
Why do two verifiers disagree on the same address?
Mostly labels and policy, not broken checks. A catch-all domain accepts mail for any address, real or made up, so no verifier can confirm a single mailbox there. Some tools call those addresses valid or deliverable; others, including SimpleVerifier, mark them risky. On a B2B list with many catch-all domains, that one choice can move the valid count by a wide margin.
The rest is timing and access. A server that greylists or rate-limits one checker can answer another an hour later, so one file says unknown where the other says valid. Role addresses (info@, sales@) and do-not-mail advice are flagged by some vendors and not others. A row where one says accepted and the other says rejected is the true conflict, and the one worth rechecking first.
Which verifier is right when they disagree?
This tool doesn't pick a winner. Agreement between two tools proves little, because both face the same limits on catch-all domains and on providers that hide mailbox status. A higher valid count isn't better on its own: a tool can raise it by counting catch-all rows as valid.
To settle it, recheck the disputed rows a day later, and send a small batch from a domain you can afford to test with, then read the bounce codes. The full protocol is in how to bench test email verifiers.
Which results files does it read?
Any CSV with an email column and a status column. Status words from ZeroBounce (valid, catch-all, unknown, do_not_mail, spamtrap), NeverBounce (valid, catchall, disposable), MillionVerifier (ok, catch_all, and good/risky/bad quality), Bouncer, Kickbox and Emailable (deliverable, risky, undeliverable, unknown), Instantly, Clay and SimpleVerifier (valid, risky, invalid) are recognised.
Yes/no columns such as Accept All, Role and Disposable, and reason columns such as ZB Sub Status or Reason, refine the explanation. A status the tool doesn't know is listed and left out of the comparison, never guessed.
How are each vendor's statuses grouped?
| Group | Status words | What it means |
|---|---|---|
| Valid | valid, ok, deliverable, verified, good | The checker reports the mailbox accepted |
| Risky | catch-all, accept_all, unknown, risky, role, do_not_mail | Not confirmed either way, or flagged for another reason |
| Invalid | invalid, undeliverable, bad, disposable, spamtrap, abuse | Expected to bounce, or not worth mailing |
Labels from each vendor's documentation, linked under Sources. Matching ignores case, spaces, dashes and underscores.
Who uses this tool, and for what?
- Teams choosing a verifier
- Run a trial list through two tools and see exactly which rows they split on, and whether the gap is catch-all policy or real conflicts.
- Teams switching verifiers
- Check that a new tool's results line up with the old one before you move every list over.
- Agencies
- When a client's verifier says valid and yours says risky, show them the rows and the reason in one file.
What can’t this tool tell you?
- It shows where two files disagree, not which one is right. Settle disputed rows with a recheck or a small test send.
- The reason comes from the status and any detail columns in the files. When a file has no detail, the reason is more general.
- Only addresses in both files are compared, matched on the full address ignoring case.
- CSV only: save a spreadsheet as CSV first. Each file can be up to 25 MB.
Common questions
- Why does another verifier show more valid emails?
- Usually catch-all domains. Their servers accept any address, so the mailbox can't be confirmed. Some tools count those addresses as valid; others mark them risky. Compare the files here to see how many of the gap rows are catch-all.
- Is a catch-all email valid?
- Not confirmed. The domain accepts mail for every address, so a check can't tell a real mailbox from a made-up one. Some of those messages bounce later or go nowhere, so send them separately in small batches.
- Can I use one verifier to check another?
- Not as an answer key. Both tools face the same limits, so agreement proves little. Use this comparison to find the disputed rows, then settle them with a recheck or a small test send.
- Are my files uploaded anywhere?
- No. Both files are read and compared in your browser. The disagreements file is built there too, so the addresses never leave the page.
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
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.