Understanding Results
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Updated Mar 08, 2026
Confidence Scores Explained
Every verification result includes a confidence score — a number that represents how certain Mailthentic is about the result. Higher scores mean greater certainty.
Score Ranges
| Score | Status | Meaning |
|---|---|---|
| 90–97 | Deliverable (Confirmed) | The mail server explicitly accepted the recipient. Very high confidence. |
| 65–78 | Deliverable (Unconfirmed) | DNS and MX are valid, but the mailbox couldn't be explicitly confirmed. Common with Google/Microsoft. |
| 50–60 | Risky | The address exists but has risk factors (catch-all domain, missing SPF/DMARC). |
| 30–45 | Unknown | Verification was inconclusive due to server timeouts or temporary errors. |
| 1–10 | Invalid | The address is definitively bad — hard bounce, bad syntax, or nonexistent domain. |
How Scores Are Calculated
The confidence score is determined by multiple factors:
- SMTP response code — A 250 (accepted) yields the highest score; a 550 (rejected) yields the lowest.
- Verification mode — SMTP mode produces higher-confidence results than DNS-only mode.
- Provider type — Known "ambiguous" providers (Google, Microsoft) that always accept recipients receive a lower score than providers that give definitive answers.
- Catch-all status — Catch-all domains reduce confidence because any address will be accepted.
- DNS security — Missing SPF or DMARC records can lower the score slightly.
Using Scores to Prioritize
For practical decision-making, we recommend these thresholds:
- Above 70 — Safe to include in marketing campaigns.
- 50–70 — Include cautiously; good for transactional emails or re-engagement flows. Monitor bounces.
- Below 50 — Exclude from cold outreach. Consider re-verifying or removing.
- Below 10 — Remove immediately.
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