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Factline Email Verification
x402
Factline Email Verification is a paid API for AI agents from factline.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).
Validates and verifies an email address for deliverability using DNS/MX checks, disposable domain detection, typo suggestions, and syntax validation, returning a single verdict of deliverable, risky, or undeliverable.
Price / call$0.002
Success—
StatusUnknown
How this service works
API and MCP servers that let AI agents and apps check people, companies, Dutch addresses and cars against official records: sanctions and PEP lists, 10 company registers, Dutch property, rent and RDW vehicle data. From $0.001 per call.
Output
A JSON object containing: overall verdict (deliverable, deliverable_role, risky, or undeliverable), syntax validity, mail routing details (MX records, null MX, implicit MX, accepts_mail, domain_exists), disposable flag, role account flag, free provider flag, domain security (SPF, DMARC policy), typo suggestion if applicable, list of human-readable reasons, and the data source used.
Example use cases
Signup form spam blocking
“Before we create an account for the user who entered 'user123@mailinator.com', check if that email is disposable or undeliverable so we can reject fake signups.”
Outreach list hygiene
“I'm about to send a cold email campaign — can you check if sarah.jones@gmial.com is actually deliverable and if there's a typo I should correct before sending?”
CRM lead validation
“We just imported a batch of leads and want to flag any bad emails — start by verifying contact@example-corp.com and tell me if it's a role address, whether the domain accepts mail, and the overall deliverability verdict.”
Technical details
Endpoint
GEThttps://factline.dev/v1/email/verify?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a fast, single-verdict email quality check that combines RFC syntax validation, live DNS/MX routing, disposable domain screening (9,000+ domains), typo detection, and role-address flagging in one call — especially for signup flows, CRM enrichment, or outreach list hygiene where you need more than basic regex but don't require SMTP mailbox probing.
Side effects
- Missing or malformed email parameter returns an error
- Domains with no DNS response may timeout or return undeliverable
- No SMTP mailbox probe — confirms domain can receive mail but not that the specific mailbox exists
- Newly registered disposable domains not yet in the blocklist may pass as deliverable
- Rare TLDs or private domains may yield incomplete MX information
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"email": "jan.jansen@gmial.com",
"domain": "gmial.com",
"source": "DNS via Cloudflare 1.1.1.1 (DNS-over-HTTPS); disposable-email-domains (CC0)",
"explain": {
"limits": "No SMTP mailbox probe: this confirms the domain can receive mail, not that this exact mailbox exists.",
"verdict": "deliverable: domain receives mail and nothing suspicious; deliverable_role: same but a shared inbox; risky: disposable domain or likely typo; undeliverable: bad syntax or the domain cannot receive mail.",
"disposable_list": "disposable-email-domains blocklist (CC0), 2026-10-07"
},
"reasons": [
"disposable (throwaway) email domain",
"possible typo of gmail.com"
],
"verdict": "risky",
"disposable": true,
"suggestion": "jan.jansen@gmail.com",
"mail_routing": {
"mx": [],
"null_mx": false,
"implicit_mx": true,
"accepts_mail": true,
"domain_exists": true
},
"role_account": false,
"syntax_valid": true,
"free_provider": false,
"domain_security": {
"spf": false,
"dmarc_policy": null
}
}
}Tags
x402
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