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BounceZero Research
Across our verification network, 12.3% of addresses are already dead - roughly one in eight bounces the moment you send. And a clean list decays fast: of addresses verified valid, only 19% are still valid when re-checked past 90 days. Verifying once and reusing the result for a quarter is close to not verifying at all.
Read the full deliverability research Source: BounceZero Deliverability Benchmarks 2026, snapshot Q3-2026.
Our 5-stage verification pipeline analyzes every email across 65+ signals - far beyond a simple format check.
Backed by original research from 10M+ real verifications — see the 2026 deliverability benchmarks.
RFC 5321 compliance, invalid characters, role-based detection (admin@, info@), disposable domain check.
DNS MX lookup, SPF/DKIM/DMARC analysis, domain age, mail server fingerprinting.
RCPT TO mailbox check, greylisting retry logic, 3-probe catch-all detection algorithm.
Gravatar presence, breach data correlation, spam trap pattern detection, provider heuristics.
Bayesian likelihood ratios blended with XGBoost and Random Forest models trained on millions of outcomes.
Every result comes with one of two verdicts, a 0-100 confidence score, and a detailed signal breakdown.
The mailbox passed verification and is deliverable. Safe to send. Confidence score typically above 75.
The mailbox was not verified as deliverable - it may not exist, be disposable, or could not be confirmed. Do not send.
Verify a prospect or contact's email before reaching out to avoid hard bounces.
Check new contact details from business cards, LinkedIn, or web forms before adding them to your CRM.
Confirm your company or personal email address is configured correctly and MX records are live.
Understand why a specific address bounced - invalid mailbox, full inbox, blocked server, or catch-all domain.
The free verifier is great for individual checks. When you need to verify thousands of addresses at once, upload a CSV and clean the whole list in minutes - 2,000 verified for $6, no subscription and no monthly minimum.
Start with 100 free credits - no card required. See pricing
Yes. You can verify individual email addresses using the demo tool above with no account required. For bulk verification or API access, sign up for a free account to receive 100 credits - no credit card needed.
SMTP verification opens a connection to the recipient mail server and issues a RCPT TO command to check if the mailbox exists - without sending an actual email. BounceZero goes further by running a 3-probe catch-all test to detect domains that accept all addresses regardless of whether the mailbox exists.
Yes. BounceZero runs three SMTP probes using randomized addresses to fingerprint catch-all behavior. If a domain accepts all addresses, we probe individual addresses against the provider to resolve them; any that stay unresolved are flagged as catch-all rather than mislabelled.
BounceZero maintains behavioral profiles for 200+ mail providers including Gmail, Outlook/Hotmail, Yahoo, and corporate domains. For providers that block SMTP probes (like Gmail), we use domain intelligence, Gravatar lookups, and ML scoring to estimate deliverability with high confidence.
Absolutely. BounceZero stores only a hashed fingerprint of each verified address for caching purposes. We never sell or share email data with third parties and are fully GDPR compliant. You can request deletion of any stored data at any time.
Start for free with 100 credits. Upload a CSV, verify via API, or add real-time validation at your sign-up form.
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