Everything you need to verify email addresses, calculate bounce rates, and embed verification on your own website - all free.
Check any email address instantly. Our 5-stage pipeline verifies syntax, MX records, SMTP delivery, catch-all status, and disposable detection - no account needed.
Single Email Verifier
Bounce Rate Calculator
Quickly calculate your email bounce rate and understand whether it's within acceptable industry thresholds.
Add a BounceZero email checker to any web page with a single iframe. Free for all websites - no API key required. Perfect for landing pages, contact pages, and demo integrations.
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<iframe src="https://bouncezero.io/embed/email-checker/" width="100%" height="120" frameborder="0" style="border-radius:12px"></iframe>
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Verify any single address instantly. No signup.
Upload a CSV and clean your entire list.
Real mailbox verification at the server level.
Integrate verification into your app or workflow.
Want the checker on your own site? Get the free email checker widget.
Detect throwaway and burner email addresses from 800+ providers.
3-probe SMTP fingerprinting to identify catch-all domains.
Check SPF, DKIM, DMARC, blacklist status, and domain reputation.
Detect pristine, recycled, and typo spam traps in your list.
Validate SPF, count DNS lookups against the 10-limit, flag common errors.
Validate policy, alignment, and rua reporting. Detect missing or duplicate records.
Auto-discover 24 common selectors. Validate keys, flag weak 1024-bit, detect revocation.
Decode the Received chain, SPF/DKIM/DMARC, hop delays, and sender IP. Private - not logged.
Check any IP against 16 major DNSBLs in one request - Spamhaus, Barracuda, SpamCop, SORBS, more.
Resolve MX records on any domain. See priorities, IPs, PTR, and auto-detect the mail provider.
Paste subject + body. Get a SpamAssassin-style 0-10 score with rule-by-rule breakdown. Content never logged.
Build a valid SPF record for 25+ ESPs (Google, M365, SendGrid, Mailgun, SES, Mailchimp...). Counts the 10-lookup limit.
Build a DMARC TXT record with policy + rua + alignment + rollout guidance. Pairs with the DMARC checker.
Need to interpret accept-all results? Read the catch-all email detection guide.
Single-email checks, no signup required
Free email open rate calculator and benchmark tool: see how your open rate compares to industry
Free cold email ROI calculator: enter your list size, reply rate, and deal size to see projected
Block temp-address signups at the source
Check if an address exists before you send
Predict a bounce before sending
Syntax, MX, SMTP, catch-all and API explained
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