Accuracy is critical for email verification. Here's what you need to know about EmailKit's accuracy and what factors can affect results.
EmailKit performs multi-step verification checks to deliver highly accurate results. Our verification process checks syntax, DNS records, MX servers, and performs SMTP-level mailbox verification.
For most standard email providers and business domains, EmailKit provides reliable deliverability signals.
Some mail servers are configured to accept email for any address at their domain, whether the mailbox exists or not. These are called "catch-all" domains.
EmailKit marks these as Risky (catch-all)
We can confirm the domain accepts mail, but we can't verify the specific mailbox
Common with corporate domains and some hosting providers
Some mail servers use greylisting — they temporarily reject the first connection and accept subsequent ones. EmailKit handles greylisting with retry logic, but in some cases this can result in a temporary "Unknown" status.
Some mail servers (especially large providers) limit the number of verification connections they accept. This can cause "Unknown" results for some emails if the server is blocking verification attempts.
If a mail server is temporarily down during verification, the result will be "Unknown". Retrying the verification later typically resolves this.
Status | Confidence | Notes |
|---|---|---|
Deliverable | High | Mailbox confirmed to exist and accept mail |
Undeliverable | High | Mailbox confirmed to not exist or domain invalid |
Risky | Medium | Email may work but has risk factors (catch-all, disposable, etc.) |
Unknown | Low | Could not determine — retry recommended |
Re-verify "Unknown" emails — Try again in a few hours. The mail server may have been temporarily unavailable
Be cautious with "Risky" — These emails may work for transactional mail but can cause issues for marketing campaigns
Trust "Deliverable" and "Undeliverable" — These results are highly reliable
Verify regularly — Email addresses change over time. A deliverable address today may not be deliverable in 3 months
No email verification service can guarantee 100% accuracy. Email deliverability depends on many factors that can change between the time of verification and the time of sending, including:
The recipient deleting their mailbox
The mail server changing its configuration
Temporary server outages during verification
Anti-spam measures that block verification attempts
EmailKit provides the most accurate assessment possible at the time of verification.
