Email list checkEmail list checkReturns JSON checking up to 20 email addresses in one call: syntax, MX records, disposable, free and role flags, SPF, DMARC and a verdict each, plus counts by verdict.
Use when you need bulk email validation, email list verification or to verify email lists before a send or import.
Do not use for one address (email-check is cheaper), proving a mailbox exists (no SMTP probe) or sending email.
Price: 0.02 USDC per call (x402, eip155:8453). Typical response time: 2500 ms (p95).
POST https://x402-gateway.blackwoodstate8.workers.dev/v1/email-batch. A request without payment gets 402 Payment Required with the
PAYMENT-REQUIRED header; any x402 client signs an EIP-3009 authorization and retries with
PAYMENT-SIGNATURE (or X-PAYMENT). Invalid input is answered with 400 and not charged.
curl -i -X POST https://x402-gateway.blackwoodstate8.workers.dev/v1/email-batch -H 'content-type: application/json' -d '{"emails":["postmaster@ietf.org","test@mailinator.com","info@example.com","not-an-email"]}'
| Pay to | 0x274508F17CDb74BbBe4241F3cA618709d0a5528c |
|---|---|
| Asset | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 (USDC) |
| Amount | 20000 atomic units (0.02 USDC) |
| Authorization window | 60 s |
Streamable HTTP at https://x402-gateway.blackwoodstate8.workers.dev/mcp, tool blackwood_email_batch. Payment goes in
_meta["x402/payment"]; without it the tool returns the payment requirements.
| Field | Type | Meaning |
|---|---|---|
emails | array | Email addresses to check, 1 to 20, e.g. ["jane@example.com", "info@ietf.org"] |
Example:
{
"emails": [
"postmaster@ietf.org",
"test@mailinator.com",
"info@example.com",
"not-an-email"
]
}
Real example:
{
"count": 4,
"domains": 3,
"summary": {
"deliverable_domain": 1,
"risky": 1,
"undeliverable": 1,
"invalid": 1,
"unknown": 0
},
"results": [
{
"email": "postmaster@ietf.org",
"normalized": "postmaster@ietf.org",
"syntaxValid": true,
"domain": "ietf.org",
"disposable": false,
"freeProvider": false,
"roleAccount": true,
"domainExists": true,
"mx": [
{
"priority": 0,
"host": "mx.ietf.org"
}
],
"acceptsMail": true,
"spf": "v=spf1 ip4:166.84.6.31 ip4:166.84.7.238 ip6:2602:f977:800:f7f6::/64 ip4:166.84.7.34 ip6:2602:f977:800::e276:63ff:fe66:3400 include:_spf.google.com include:spf.hostedrt.com ~all",
"dmarc": "v=DMARC1; p=none; rua=mailto:dmarc_agg@vali.email,mailto:dmarc-report@ietf.org",
"dmarcPolicy": "none",
"verdict": "deliverable_domain",
"reasons": [
"role_account"
],
"smtpChecked": false
},
{
"email": "test@mailinator.com",
"normalized": "test@mailinator.com",
"syntaxValid": true,
"domain": "mailinator.com",
"disposable": true,
"freeProvider": false,
"roleAccount": false,
"domainExists": true,
"mx": [
{
"priority": 1,
"host": "mail.mailinator.com"
},
{
"priority": 1,
"host": "mail2.mailinator.com"
}
],
"acceptsMail": true,
"spf": "v=spf1 -all",
"dmarc": "v=DMARC1;p=reject;sp=reject;aspf=s;pct=100",
"dmarcPolicy": "reject",
"verdict": "risky",
"reasons": [
"disposable"
],
"smtpChecked": false
},
{
"email": "info@example.com",
"normalized": "info@example.com",
"syntaxValid": true,
"domain": "example.com",
"disposable": false,
"freeProvider": false,
"roleAccount": true,
"domainExists": true,
"mx": [],
"acceptsMail": false,
"spf": "v=spf1 -all",
"dmarc": "v=DMARC1;p=reject;sp=reject;adkim=s;aspf=s",
"dmarcPolicy": "reject",
"verdict": "undeliverable",
"reasons": [
"null_mx",
"role_account"
],
"smtpChecked": false
},
{
"email": "not-an-email",
"normalized": null,
"syntaxValid": false,
"domain": null,
"disposable": false,
"freeProvider": false,
"roleAccount": false,
"domainExists": null,
"mx": [],
"acceptsMail": false,
"spf": null,
"dmarc": null,
"dmarcPolicy": null,
"verdict": "invalid",
"reasons": [
"syntax"
],
"smtpChecked": false
}
]
}
{
"type": "object",
"properties": {
"count": {
"type": "number"
},
"domains": {
"type": "number"
},
"summary": {
"type": "object",
"properties": {
"deliverable_domain": {
"type": "number"
},
"risky": {
"type": "number"
},
"undeliverable": {
"type": "number"
},
"invalid": {
"type": "number"
},
"unknown": {
"type": "number"
}
},
"required": [
"deliverable_domain",
"risky",
"undeliverable",
"invalid",
"unknown"
],
"additionalProperties": false
},
"results": {
"type": "array",
"items": {
"type": "object",
"properties": {
"email": {
"type": "string"
},
"normalized": {
"type": [
"string",
"null"
]
},
"syntaxValid": {
"type": "boolean"
},
"domain": {
"type": [
"string",
"null"
]
},
"disposable": {
"type": "boolean"
},
"freeProvider": {
"type": "boolean"
},
"roleAccount": {
"type": "boolean"
},
"domainExists": {
"type": [
"boolean",
"null"
]
},
"mx": {
"type": "array",
"items": {
"type": "object",
"properties": {
"priority": {
"type": "number"
},
"host": {
"type": "string"
}
},
"required": [
"priority",
"host"
],
"additionalProperties": false
}
},
"acceptsMail": {
"type": "boolean"
},
"spf": {
"type": [
"string",
"null"
]
},
"dmarc": {
"type": [
"string",
"null"
]
},
"dmarcPolicy": {
"type": [
"string",
"null"
]
},
"verdict": {
"type": "string",
"enum": [
"deliverable_domain",
"risky",
"undeliverable",
"invalid",
"unknown"
]
},
"reasons": {
"type": "array",
"items": {
"type": "string"
}
},
"smtpChecked": {
"type": "boolean"
}
},
"required": [
"email",
"normalized",
"syntaxValid",
"domain",
"disposable",
"freeProvider",
"roleAccount",
"domainExists",
"mx",
"acceptsMail",
"spf",
"dmarc",
"dmarcPolicy",
"verdict",
"reasons",
"smtpChecked"
],
"additionalProperties": false
}
},
"next": {
"type": "object",
"properties": {
"service": {
"type": "string",
"description": "Service id of the suggested next paid call"
},
"tool": {
"type": "string",
"description": "MCP tool name of the same call"
},
"method": {
"type": "string",
"enum": [
"GET",
"POST"
]
},
"url": {
"type": "string",
"description": "Paid route of the next call"
},
"useWhen": {
"type": "string",
"description": "When the next call is the right one"
},
"sample": {
"type": "string",
"description": "Free fixed sample of the whole family"
}
},
"required": [
"service",
"tool",
"method",
"url",
"useWhen",
"sample"
],
"additionalProperties": false,
"description": "Suggested next paid call in the same family (call it in a loop when the task continues)"
}
},
"required": [
"count",
"domains",
"summary",
"results"
],
"additionalProperties": false
}Free schema and example: GET https://x402-gateway.blackwoodstate8.workers.dev/v1/email-batch.
OpenAPI 3.1 · llms.txt · All services