Email Verification API

Real-time email verification API. Syntax, MX, disposable detection, role-based flags, quality score 0-100. Built for agent outreach pipelines. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

{
  "mcpServers": {
    "email-verification": {
      "url": "https://email-verification.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://email-verification.api.klymax402.com/api/verify" \
  -H "Content-Type: application/json" \
  -d '{"email":"user@example.com"}'
# -> 402 Payment Required, with an x402 payment challenge in the response body

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

email_verify_address

Verify email deliverability in real-time. Alternative to Hunter email-verifier at 15x lower cost. Returns a structured JSON report with syntax, MX, disposable detection, role-based flags, and quality score 0-100.

Parameters

Example response:

{"valid":true,"syntax":true,"mx":true,"disposable":false,"role":false,"free":true,"score":85,"email":"john@gmail.com"}

When to use: sending outreach emails, adding contacts to CRM, or processing signups. Essential for verifying email deliverability, cleaning email lists, detecting fake registrations, and qualifying leads. Drop-in replacement for Hunter email verification.

Not for: finding emails (use email_find_by_name), person data (use person_enrich_from_email), domain deliverability audit (SPF/DKIM/DMARC) (use email_audit_deliverability).

email_verify_batch

Use this when you need to validate multiple email addresses at once (up to 100). Returns a JSON array of verification results plus summary counts.

Parameters

Example response:

{"results":[{"email":"a@test.com","valid":true,"score":90},{"email":"b@mailinator.com","valid":false,"score":10}],"summary":{"total":2,"valid":1,"invalid":1,"disposable":1}}

When to use: bulk list cleaning, CRM hygiene, or pre-campaign validation. Essential when you have 5+ emails to verify at once.

Not for: single emails (use email_verify_address), finding emails (use email_find_by_name).

Example agent prompts

• "Verify email deliverability in real-time"
• "Validate multiple email addresses at once (up to 100)"

Payment

• Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
• Network: Base L2 (eip155:8453)
• Asset: USDC
• Facilitator: Coinbase CDP (primary), PayAI (fallback)
• Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)

Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

• Catalog: https://klymax402.com/llms.txt
• Full API reference: https://klymax402.com/llms-full.txt
• Live stats: https://klymax402.com/stats

License

MIT