Understanding results
Every MailSentry response includes a score, verdict, and detailed checks. Here's how to read them.
Anatomy of a response
When you verify an email, the response tells you three things at a glance:
- Score (0-100) — a single number summarizing how safe this address is. 100 means everything checks out; 0 means it's definitely invalid.
- Verdict — a human-readable label:
valid,caution,risky, orinvalid. - Recommendation — a plain-English action: "Safe to send", "Send with caution", "Do not send".
Below those top-level fields, the checks object contains the per-layer breakdown — the raw results from each of the 11 validation layers.
What the verdicts mean
| Score | Verdict | What to do |
|---|---|---|
| 90–100 | valid | Send with confidence. The mailbox exists, the domain is healthy, and no risk signals were found. Covered by our accuracy guarantee on paid plans. |
| 60–89 | caution | Send transactional emails. Review before marketing sends. Usually means a role-based address (info@, sales@), a catch-all domain, or SMTP couldn't fully confirm the mailbox. Check the checks object to see which flag triggered it and decide based on your use case. |
| 30–59 | risky | Don't send marketing. Add friction for signups. Usually means a gibberish local part on a catch-all domain, a very new domain, or a spam-trap pattern. For signup flows, require phone verification or CAPTCHA. For existing lists, move these to a quarantine segment. |
| 0–29 | invalid | Don't send. Block or correct. This address will bounce — bad syntax, dead domain, nonexistent mailbox, or disposable provider. If a typo was detected, show the user the suggested correction instead of a generic error. |
Verification levels
The verification_level field tells you how confidently we could verify the address:
- confirmed — the mail server explicitly confirmed this mailbox exists (SMTP verified).
- inferred — the domain is catch-all, so the server accepts everything. We can't confirm individual mailboxes.
- estimated — SMTP was inconclusive (timeout or greylisting). The score is based on the other 10 checks.
How to act on results
For most use cases, a simple rule works well:
- Score 60+ — allow the email through. It's either clean or has only minor flags.
- Score 30-59 — flag for review. Ask the user to confirm, or skip in marketing sends.
- Score below 30 — reject or remove. This address will bounce or worse.
For real-time signup forms, we recommend blocking anything below 60 and showing a helpful message: "This email doesn't look right. Did you mean gmail.com?" (use the typo.suggestion field when available).