Resources
How NexiphorVerifier actually classifies addresses. No invented accuracy percentages.
- What is email verification?
Email verification checks whether an address can receive mail. NexiphorVerifier uses syntax, DNS/MX, and SMTP RCPT probes — not a guess.
- Email verification vs validation
Validation often means syntax. Verification means asking the mail system. NexiphorVerifier does both, then returns Valid, Invalid, Risky, or Unknown.
- How SMTP verification works
An SMTP mailbox probe connects to the receiving MX, issues RCPT TO, and records the reply. That is how NexiphorVerifier checks a mailbox without sending a message.
- What is a catch-all domain?
A catch-all domain accepts RCPT TO for any local part. NexiphorVerifier marks those addresses Risky — not Valid — because the mailbox may still bounce.
- What does Risky mean?
Risky means the probe could not prove the mailbox exists. Catch-alls, gateway accepts, and similar cases stay Risky so they are not exported as safe to send.
- Why email verifiers return Unknown
Unknown means the probe timed out, was blocked, or otherwise could not finish. NexiphorVerifier refunds Unknown instead of guessing Valid or Invalid.
- How to verify a CSV email list
Upload a CSV, Excel, JSON, or pasted list. Watch bulk progress, then export Valid only or Valid plus high-confidence catch-alls.
- Email verification API guide
Call POST /api/v1/verify/single or bulk with a Bearer nxv_ key. Poll the job, or wait synchronously on single verify. See the full /docs reference.
- Valid vs Invalid vs Risky vs Unknown
The four NexiphorVerifier statuses: mailbox exists, mailbox rejected, accepted without proof, or the probe could not finish (refunded).
- Email verification before cold email
Clean the list before the sequence. Catch-alls stay Risky. Unknown credits come back. Sending dead mailboxes burns the domain.
Product: Why NexiphorVerifier · API docs · Pricing