Horizon Pulse Email API

openapi: 3.2.0
info:
  title: Horizon Pulse Email API
  version: 1.1.0
  termsOfService: https://horizonpulse.dev/terms/buyer
  summary: Pay-per-call APIs for AI agents, settled in USDC on Base, Solana or Polygon, or RLUSD on the XRP Ledger, with x402.
  description: 'Pay-per-call APIs for AI agents, paid in USDC on Base, Solana or Polygon, or RLUSD on the XRP Ledger, with x402: web search, page fetch and extract, PDF to text, an HTTP proxy, and crypto market data. No signup or API key.


    On Base, you only pay for a successful response; errors are not charged except where an operation says so (for /api/tx-status, a not_found status is a charged answer; poll again after pollAgainSeconds). These no-charge statements are made for USDC on Base. On USDC on Solana, and RLUSD on the XRP Ledger, a refused or failed request may still be charged. charged: false means Horizon Pulse did not settle the payment; on USDC on Solana, and RLUSD on the XRP Ledger, this is not a guarantee that no funds moved. Every paid operation carries `x-payment-info` with the exact price, asset, network and payTo of its Base entry; these match the 402 challenge and https://horizonpulse.dev/.well-known/x402. The 402 challenge also offers the same price in USDC on Solana mainnet (`exact`, network solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp, USDC mint EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v, payTo BjY98A6dS3GGLZdz2zHy8wK7XAwnQgNhCc66mfmBTRPz, PayAI facilitator https://facilitator.payai.network), and in native USDC on Polygon PoS mainnet (`exact`, network eip155:137, USDC 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359, payTo 0x5b32c973596078a967562ca652761404f19be0e9, facilitator: Coinbase CDP), and in RLUSD on the XRP Ledger mainnet (`exact`, network xrpl:0, currency RLUSD = 524C555344000000000000000000000000000000, issuer rMxCKbEDwqr76QuheSUMdEGf4B9xJ8m5De, payTo r3FbirL83RAB2CwnUdxE5pCohMkuo6LQcf, verified on the validated ledger). Recorded example responses (fixed input, dated, informational; not paid operations): GET /api/demo/{route}.


    Agent integration: step-by-step skill at https://horizonpulse.dev/skill.md; guide with MCP setup at https://horizonpulse.dev/agents (hosted MCP at https://horizonpulse.dev/mcp for x402-aware clients, plus a local stdio MCP server in the repo''s mcp/ folder that pays from your own wallet with spend caps).


    Services for API owners (web pages, not API operations; not paid via x402): Bazaar listing fix at https://horizonpulse.dev/listing-fix; agent promotion at https://horizonpulse.dev/agent-promotion.'
  contact:
    name: Horizon Pulse
    email: horizonpulse.co@proton.me
    url: https://horizonpulse.dev
  x-guidance: 'Read PAYMENT-REQUIRED (base64 JSON). Pay exact USDC on Base (CDP), Solana (PayAI feePayer), Polygon, or RLUSD on XRPL at the listed payTo. Unpaid samples: /api/demo/{route}. Skill: /skill.md. Hosted MCP: /mcp (Base USDC only).'
servers:
- url: https://horizonpulse.dev
  description: Production
security:
- x402: []
tags:
- name: Email
paths:
  /api/email/check:
    get:
      operationId: getEmailCheck
      summary: Email address check ($0.003)
      description: 'Email address check for one address: RFC 5322 syntax, MX records (null MX noted), SPF and DMARC records over DNS, role-account flag (info@, admin@ and similar) and a disposable-domain match. No SMTP connection is made, so mailbox existence is not checked. One address per call. Bad input or DNS failure: Not charged. USDC on Base or Polygon. On USDC on Base, errors are not charged, apart from the exceptions noted on a route. On USDC on Solana, and RLUSD on the XRP Ledger, a refused or failed request may still be charged. On Polygon (native USDC), a request is settled only when it succeeds (HTTP status below 400). Failed requests are not charged.'
      x-payment-info:
        protocol: x402
        x402Version: 2
        scheme: exact
        network: eip155:8453
        asset: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
        assetSymbol: USDC
        decimals: 6
        priceUsd: $0.003
        amount: '3000'
        payTo: '0x5b32c973596078a967562ca652761404f19be0e9'
        facilitator: https://api.cdp.coinbase.com/platform/v2/x402
        networks:
        - eip155:8453
        - eip155:137
        polygon:
          network: eip155:137
          asset: '0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359'
          payTo: '0x5b32c973596078a967562ca652761404f19be0e9'
      responses:
        '200':
          description: Result.
          content:
            application/json:
              schema:
                type: object
        '400':
          description: Bad input. Not charged.
          content:
            application/json:
              schema:
                type: object
        '402':
          description: 'Payment required: PAYMENT-REQUIRED header, $0.003 USDC on Base or Polygon.'
          content:
            application/json:
              schema:
                type: object
      tags:
      - Email
components:
  securitySchemes:
    x402:
      type: apiKey
      in: header
      name: PAYMENT-SIGNATURE
      description: x402 v2 payment payload (base64 JSON), built from the 402 PAYMENT-REQUIRED challenge. No account or API key. See https://www.x402.org/.
externalDocs:
  description: 'Agent guide: discovery, the x402 pay flow, skill file and MCP setup'
  url: https://horizonpulse.dev/agents