# DomainCheck Email Validator

> DomainCheck Email Validator is a paid API for AI agents from api.youraitools.co, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-26).

Validates an email address for syntax, domain deliverability, disposability, and authentication quality, returning a scored verdict with risk flags.

## Facts

- Endpoint: GET https://api.youraitools.co/domaincheck/v1/email?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-26
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/domaincheck-email-validator-bba60b16
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_33CT1xDIjqq2G9gfpMgGj

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability domaincheck-email-validator-bba60b16
```

Example prompt: Can you check whether jane.doe+news@gmail.com is a valid, deliverable email address and tell me if there are any risk flags or authentication issues with the domain?

## When to prefer this

Choose this endpoint when you need a fast, scored email validation that goes beyond syntax checking — covering domain MX existence, authentication policy (SPF/DMARC), disposable/free-provider detection, and risk flagging. Prefer it over simple regex validators when you need actionable risk signals for onboarding, lead qualification, or mailing list hygiene. Note it does not perform SMTP RCPT probing, so it cannot confirm individual mailbox existence.

## Known failure modes

- Missing or malformed 'email' query parameter returns an error
- Non-existent or unreachable domain may return low score with deliverability flags
- SMTP mailbox existence is NOT checked — verdict reflects domain-level deliverability only
- Very new domains may lack DNS records, resulting in incomplete auth grades
- Rate limits or payment failures (x402) may block the request

## How this service works

Email address check for AI agents (signups, outreach, fraud screening): RFC syntax, disposable / role / free-provider detection, MX and null-MX, SPF/DMARC of the domain, domain age via RDAP, parking, verdict (valid | risky | undeliverable | invalid) and 0-100 score. No SMTP probing, no data stored.

## Output

A JSON object containing: a numeric deliverability score (0–100), a verdict string (e.g. 'valid'), syntax validity, canonical and normalized email forms, local part and domain, plus_tag if present, disposable flag, free_provider flag, MX records with priorities, domain authentication grades (SPF, DMARC), risk flags with severity and penalty, DNS query count, engine version, and processing time in milliseconds.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "email"
     ],
     "properties": {
      "email": {
       "type": "string",
       "description": "Email address to check, e.g. \"jane@example.com\""
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ms": 40,
  "note": "Mailbox existence is not probed (no SMTP RCPT check). \"valid\" means the address is well-formed, the domain accepts mail and nothing looks risky.",
  "role": false,
  "tier": "full",
  "flags": [
   {
    "id": "free_email_provider",
    "penalty": 0,
    "severity": "info",
    "description": "Free webmail provider (gmail.com, outlook.com ...)."
   },
   {
    "id": "dmarc_none",
    "penalty": 5,
    "severity": "low",
    "description": "DMARC policy is p=none (monitoring only, no enforcement)."
   }
  ],
  "input": "jane.doe+news@gmail.com",
  "local": "jane.doe+news",
  "score": 95,
  "domain": "gmail.com",
  "engine": "domaincheck-2026.10.21",
  "syntax": {
   "valid": true,
   "reason": null
  },
  "verdict": "valid",
  "plus_tag": "news",
  "smtputf8": false,
  "canonical": "janedoe@gmail.com",
  "disposable": false,
  "normalized": "jane.doe+news@gmail.com",
  "dns_queries": 6,
  "domain_auth": {
   "spf": "redirect",
   "dmarc": "none",
   "grade": "D"
  },
  "registration": null,
  "free_provider": true,
  "deliverability": {
   "mx": [
    {
     "host": "gmail-smtp-in.l.google.com",
     "priority": 5
    },
    {
     "host": "alt1.gmail-smtp-in.l.google.com",
     "priority": 10
    },
    {
     "host": "alt2.gmail-smtp-in.l.google.com",
     "priority": 20
    },
    {
     "host": "alt3.gmail-smtp-in.l.google.com",
     "priority": 30
    },
    {
     "host": "alt4.gmail-smtp-in.l.google.com",
     "priority": 40
    }
   ],
   "null_mx": false,
   "mx_provider": "Google Workspace / Gmail",
   "accepts_mail": true,
   "domain_exists": true
  },
  "mailbox_checked": false
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/domaincheck-email-validator-bba60b16/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.youraitools.co](https://www.zero.xyz/host/api.youraitools.co/llms.txt)