Integrate email verification directly into your sign-up forms, CRM pipelines, and data workflows with a single API call. BounceZero returns 65+ signal fields in JSON - including classification, score, SMTP result, catch-all status, and plain-English explanation.
One endpoint. Three lines of code. Works with any stack.
# Single email verification
curl -X POST https://bouncezero.io/api/v1/verify \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"email": "[email protected]", "depth": "standard"}'A rich JSON object with everything you need to make a reliable accept/reject decision.
{
"email": "[email protected]",
"classification": "deliverable",
"score": 87.4,
"confidence": 0.91,
"is_deliverable": true,
"risk_level": "low",
"domain": {
"mx_valid": true,
"is_catchall": false,
"is_disposable": false,
"spf": true,
"dmarc": true,
"provider": "Google Workspace"
},
"smtp": {
"connected": true,
"mailbox_exists": true,
"response_code": 250
},
"flags": {
"is_role_based": false,
"is_free_provider": false
},
"explanation": "Valid mailbox confirmed...",
"response_time_ms": 1243
}classification
string
Result category: deliverable, risky, undeliverable, or unknown.
score
float 0-100
Composite deliverability score. >75 = safe to send, 30-75 = risky, <30 = do not send.
confidence
float 0-1
How confident the scoring engine is in the classification.
is_deliverable
boolean
Convenience boolean: true when score ≥ 75 and classification is deliverable.
domain.is_catchall
boolean
True when the domain accepts all addresses regardless of mailbox existence.
domain.is_disposable
boolean
True when the domain is a known temporary or throwaway email provider.
smtp.mailbox_exists
boolean
True when the SMTP server confirmed the mailbox (RCPT TO 250 OK).
explanation
string
Plain-English explanation of why this result was returned.
Reject invalid and disposable email addresses at the point of collection - before they enter your database and ESP contact list.
Verify contacts on import or export. Flag stale addresses for re-engagement campaigns before they generate bounces.
Validate customer email at checkout to ensure order confirmations and receipts reach real inboxes.
Stop wasting ad spend on leads with invalid emails. Validate at the form level and only count real, deliverable addresses.
Enrich contact records in your data pipeline with deliverability signals. Route only valid contacts to downstream marketing tools.
Trigger email verification on HubSpot, Salesforce, or Zapier events. Automatically mark contacts as valid or invalid in your CRM.
Cached addresses return in under 100ms. Fresh SMTP verifications typically complete in 1-3 seconds. The depth parameter lets you control the trade-off: basic returns in <50ms (syntax + domain only), standard adds SMTP, and deep includes social signals.
Yes. All new accounts receive 100 free verification credits with API access - no credit card required. This is enough to prototype your integration and test the full response schema before committing to a paid plan.
Free tier: 10 requests/minute. Starter: 60 req/min. Pro: 300 req/min. Enterprise: custom rate limits available. Rate limit headers (X-RateLimit-Remaining, X-RateLimit-Reset) are included in every response.
Yes. The POST /api/v1/verify/bulk endpoint accepts up to 1,000 addresses per request and returns an async job ID. Poll GET /api/v1/jobs/{id} for status and results. See our full documentation for the bulk API spec.
Sign up in 30 seconds, grab your API key, and make your first verification call. 100 free credits included.
Single-email checks, no signup required
Verify a single address instantly
Verify a whole list up to your free monthly credits
Check if any email address is real
Validate email before you send
See exactly what an MX server says
Find which domains accept anything
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