Use when you need email validation or to verify email addresses (domain, MX reco
Use when you need email validation or to verify email addresses (domain, MX records) before sending, signup or lead scoring. Do not use for confirming that the mailbox itself exists (no SMTP probe is done) or sending email. Returns JSON with an email address check: syntax, domain and MX records, disposable, free and role account flags, SPF and DMARC, and a verdict on whether the domain can receive mail for 0.005 USDC per call. Typical response time 800 ms (p95). Category: Data.
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://x402-gateway.blackwoodstate8.workers.dev/v1/email-check
| Category | Everything else |
|---|---|
| Provider host | x402-gateway.blackwoodstate8.workers.dev |
| Networks | eip155:8453 |
| Payment schemes | exact, upto |
| Self-reported calls, 30 days | 6 from 3 payers (the provider's figure, not ours) |
Our checks, last 30 days
We never call tools that send, buy, move money or file anything, not even without paying.
Example input (from the provider)
{
"body": {
"email": "postmaster@ietf.org"
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"email": {
"description": "Email address to check, e.g. jane@example.com",
"maxLength": 254,
"minLength": 3,
"type": "string"
}
},
"required": [
"email"
],
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"additionalProperties": false,
"properties": {
"acceptsMail": {
"type": "boolean"
},
"disposable": {
"type": "boolean"
},
"dmarc": {
"type": [
"string",
"null"
]
},
"dmarcPolicy": {
"type": [
"string",
"null"
]
},
"domain": {
"type": [
"string",
"null"
]
},
"domainExists": {
"type": [
"boolean",
"null"
]
},
"email": {
"type": "string"
},
"freeProvider": {
"type": "boolean"
},
"mx": {
"items": {
"additionalProperties": false,
"properties": {
"host": {
"type": "string"
},
"priority": {
"type": "number"
}
},
"required": [
"priority",
"host"
],
"type": "object"
},
"type": "array"
},
"next": {
"additionalProperties": false,
"description": "Suggested next paid call in the same family (call it in a loop when the task continues)",
"properties": {
"method": {
"enum": [
"GET",
"POST"
],
"type": "string"
},
"sample": {
"description": "Free fixed sample of the whole family",
"type": "string"
},
"service": {
"description": "Service id of the suggested next paid call",
"type": "string"
},
"tool": {
"description": "MCP tool name of the same call",
"type": "string"
},
"url": {
"description": "Paid route of the next call",
"type": "string"
},
"useWhen": {
"description": "When the next call is the right one",
"type": "string"
}
},
"required": [
"service",
"tool",
"method",
"url",
"useWhen",
"sample"
],
"type": "object"
},
"normalized": {
"type": [
"string",
"null"
]
},
"reasons": {
"items": {
"type": "string"
},
"type": "array"
},
"roleAccount": {
"type": "boolean"
},
"smtpChecked": {
"type": "boolean"
},
"spf": {
"type": [
"string",
"null"
]
},
"syntaxValid": {
"type": "boolean"
},
"verdict": {
"enum": [
"deliverable_domain",
"risky",
"undeliverable",
"invalid"
],
"type": "string"
}
},
"required": [
"email",
"normalized",
"syntaxValid",
"domain",
"disposable",
"freeProvider",
"roleAccount",
"domainExists",
"mx",
"acceptsMail",
"spf",
"dmarc",
"dmarcPolicy",
"verdict",
"reasons",
"smtpChecked"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}