Validate any email address in real time. Our 5-stage checker verifies syntax, DNS/MX records, SMTP deliverability, catch-all domains, and disposable email detection - all in under 3 seconds.
Five layers of validation run in sequence. Each layer adds precision that basic format-checkers can't provide.
RFC 5321 compliance, invalid characters, length limits, plus+ addressing, international domain support.
Verifies the domain has active mail exchange records. No MX = undeliverable, no SMTP probe needed.
Opens a connection to the mail server and issues RCPT TO to confirm the mailbox exists - without sending any email.
3-probe technique distinguishes real mailboxes from catch-all domains that accept everything.
Disposable domain check, role-address detection (admin@, info@), spam trap signals, ML scoring for edge cases.
People use these terms interchangeably, but they mean different things technically.
Validation checks the format and structure of an address: is it RFC-compliant, does the domain exist, are MX records configured? It's fast (milliseconds) and requires no outbound connections.
Verification goes further: it proves the mailbox exists using SMTP probes. It also detects catch-all domains, disposable addresses, spam traps, and role accounts - giving you a deliverability score, not just a format check.
Not all invalid results are the same. Understanding the error type tells you exactly what action to take.
The address doesn't conform to RFC 5321. Common causes: double dots (jo..hn@), space inside the address, missing @, invalid characters. Action: reject at capture and prompt the user to re-enter.
The domain doesn't have mail exchange records configured. No email can ever be delivered to this domain. Action: treat as hard bounce - remove immediately.
The mail server returned a permanent rejection for this specific mailbox. The address doesn't exist. Action: remove from list, suppress future sends.
The mail server accepts any address regardless of whether a mailbox exists. We probe individual addresses against the provider to resolve them; any that stay unresolved are flagged as catch-all rather than mislabelled.
The domain belongs to a temporary email provider (Guerrilla Mail, Mailinator, etc.). The address was likely created to bypass a signup gate. Action: block at signup, remove from lists.
The local part suggests a shared mailbox (info@, admin@, support@, sales@). These have high unsubscribe rates and often hit spam folders. Action: flag and decide based on your use case.
The server didn't respond in time. Could be rate limiting, greylisting, or a slow server. Action: retry - BounceZero retries automatically; most resolve to a definitive verdict on the second probe.
A proper email address validator checks five things: (1) syntax and format - RFC 5321 compliance; (2) MX records - whether the domain has mail servers configured; (3) SMTP handshake - whether the specific mailbox accepts delivery; (4) catch-all detection - whether the domain accepts all addresses regardless; (5) disposable/temporary email detection. BounceZero runs all five checks in under 3 seconds.
Yes. You can validate individual email addresses with no account required. For bulk validation or API access, sign up for a free account to receive 100 credits monthly - no credit card needed.
Email validation typically refers to checking the format and syntax of an email address. Email verification goes further - it uses DNS lookups and SMTP probes to confirm the mailbox actually exists on the mail server. BounceZero does both.
Yes. BounceZero has dedicated validation logic for Gmail, Google Workspace, Microsoft 365, Outlook.com, Yahoo, iCloud, and all major ISPs. Each provider requires different SMTP handling - BounceZero adapts automatically.
BounceZero achieves up to 99.8% accuracy in internal testing on SMTP-verifiable addresses on verifiable addresses. For catch-all domains, we probe individual addresses against the provider to resolve them; any that stay unresolved are flagged as catch-all rather than mislabelled.
BounceZero's bulk validator processes up to 10 million addresses per job. Upload a CSV, get clean results in minutes. $3 per 1,000. Credits never expire.
No credit card - 100 free validations every month - Results in minutes
Single-email checks, no signup required
Block temp-address signups at the source
Verify a single address instantly
Check if any email address is real
Validate email before you send
Verify a whole list up to your free monthly credits
See exactly what an MX server says
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