Frequently Asked Questions

Our verification process uses a multi-step approach: First, we validate the email syntax against RFC 5322 standards. Then, we check if the domain exists and has valid MX (mail exchange) records. Finally, we perform an SMTP handshake with the mail server to confirm the mailbox exists—all without sending an actual email.

Disposable emails (also called temporary or throwaway emails) are addresses from services like Mailinator, 10MinuteMail, or Guerrilla Mail that users create for one-time use. They're often used to bypass signup requirements and typically become invalid within hours. Our API detects these to help you maintain list quality.

A catch-all domain is configured to accept emails sent to any address @domain.com, even if that specific mailbox doesn't exist. This makes SMTP verification inconclusive. We flag these domains so you can decide whether to accept them based on your risk tolerance—they may be valid, but we can't confirm the specific mailbox.

Role-based emails are addresses like info@, support@, sales@, or admin@ that represent a function or department rather than an individual. They often have multiple recipients or are managed by different people over time. We flag these because they may have higher bounce rates or lower engagement for personal outreach.

No, credits never expire. Once you purchase credits, they remain in your account until you use them. This makes MailValid perfect for projects with variable verification needs—buy credits when you need them, use them at your own pace.

A fresh completed result uses 1 credit. Invalid addresses are billable because they are completed checks that help you avoid bounces. Duplicate emails in the same bulk upload and inconclusive checks are free.

No. MailValid only deducts a credit when a verification returns a final, actionable result: valid, invalid, catch_all, or do_not_mail. If a verification returns unknown, no credit is deducted. Unknown results are automatically skipped in both single and bulk verification, so you only pay for verifications that produce a usable result.

Every new account gets 100 free credits. These credits never expire and let you fully test the API before purchasing more. No credit card required to sign up.

Yes. Free is limited to 10 requests/min and 100 emails per bulk job. Every paid plan — MailValid Plus and pay-as-you-go — gets 200 requests/min and up to 10,000 emails per bulk job. For higher limits, contact us to discuss your needs.

Our average response time is under 500ms for single email verifications. Most verifications complete in 200-400ms. SMTP verification may take longer for some domains depending on their mail server response times.

99% accuracy for deliverable/undeliverable determinations. Some limitations exist: catch-all domains can't be definitively verified, and some corporate mail servers block SMTP verification. We clearly flag these cases in the API response.