openapi: 3.1.0
info:
  title: Email Verifier & Validator
  description: Takes one email address and tells you whether it can actually receive mail. Returns a verdict of
    valid, invalid, or risky, splits the address into username and domain, and flags free providers and role accounts
    like admin@ or support@. One address per call.
  version: 1.0.0
  contact:
    name: _done
    url: https://forms.gle/5KzuSFH7p8hHtDmz7
    email: info@underscoredone.com
  x-openapi-url: https://email-verifier.underscoredone.com/openapi.json
  x-logo:
    url: https://underscoredone.com/logo.png
    altText: _done
  x-guidance: 'Call this before sending an email or accepting a signup address. Send exactly one email string per
    call, already trimmed if possible. Check the quality field: treat ''invalid'' as do-not-send, ''risky'' as send-with-caution,
    ''valid'' as safe. Use free and role flags to decide if the address is a personal inbox worth trusting. Do not
    send arrays or multiple addresses in one call.'
  x-ai-instructions: 'Call this before sending an email or accepting a signup address. Send exactly one email string
    per call, already trimmed if possible. Check the quality field: treat ''invalid'' as do-not-send, ''risky''
    as send-with-caution, ''valid'' as safe. Use free and role flags to decide if the address is a personal inbox
    worth trusting. Do not send arrays or multiple addresses in one call.'
  x-provider: _done — single-purpose utility APIs for developers and AI agents. Pay per call with USDC on Base Mainnet
    or Solana Mainnet.
  x-pricing:
    model: pay-per-call
    currency: USDC
    network: Base Mainnet or Solana Mainnet
    price: $0.01
  x-keywords:
  - email verifier
  - email validator
  - email checker
  - deliverability check
  - verify email address
  - role account detector
  - free email detector
  - mailbox check
  - bounce prevention
  - email cleaning
  - signup validation
  - utility
  - api
  - ai-agent
  - pay-per-call
  - usdc
  - x402
  - network
  - email verification
  - mail server
  x-category: network
  x-provider-url: https://underscoredone.com
  x-agentcash-auth:
    mode: paid
  x-402:
    price: $0.01
    network: eip155:8453
    asset: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
    pay_to: '0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08'
    facilitator: https://api.cdp.coinbase.com/platform/v2/x402
    scheme: exact
    description: Takes one email address and tells you whether it can actually receive mail. Returns a verdict of
      valid, invalid, or risky, splits the address into username and domain, and flags free providers and role accounts
      like admin@ or support@. One address per call.
    mime_type: application/json
    networks:
    - network: eip155:8453
      asset: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
      pay_to: '0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08'
    - network: solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp
      asset: EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v
      pay_to: 8ugAWAXDB8V18kiUrGZTq1oMvU3C6Fxs8hfC6rvzQT3b
paths:
  /verify:
    post:
      tags:
      - Network
      - Email Verification
      - Signup Validation
      - Mail Server
      summary: Verify if an email address is real and safe to send to
      description: Checks one email address and reports whether it looks safe to send mail to, along with helpful
        details about it.
      operationId: verify_email_verify_post
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Request'
        required: true
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Response'
              examples:
                success:
                  summary: Successful response
                  value:
                    api_version: 1.0.0
        '422':
          description: Unprocessable — a required field is missing or the wrong type. Check the detail field for
            specifics.
          content:
            application/json:
              schema:
                type: object
                properties:
                  detail:
                    type: array
        '402':
          description: Payment required. Send a signed USDC payment on Base Mainnet or Solana Mainnet using the
            x402 protocol.
          headers:
            X-Payment-Response:
              description: x402 payment challenge — base64-encoded JSON with payment details.
              schema:
                type: string
        '400':
          description: Bad request — your input failed validation or could not be processed. Check the detail field
            for specifics.
          content:
            application/json:
              schema:
                type: object
                properties:
                  detail:
                    type: string
      x-ai-instructions: 'Call this before sending an email or accepting a signup address. Send exactly one email
        string per call, already trimmed if possible. Check the quality field: treat ''invalid'' as do-not-send,
        ''risky'' as send-with-caution, ''valid'' as safe. Use free and role flags to decide if the address is a
        personal inbox worth trusting. Do not send arrays or multiple addresses in one call.'
      x-guidance: 'Call this before sending an email or accepting a signup address. Send exactly one email string
        per call, already trimmed if possible. Check the quality field: treat ''invalid'' as do-not-send, ''risky''
        as send-with-caution, ''valid'' as safe. Use free and role flags to decide if the address is a personal
        inbox worth trusting. Do not send arrays or multiple addresses in one call.'
      x-payment-info:
        price:
          fixed:
            mode: fixed
            currency: USD
            amount: '0.01'
        protocols:
        - x402: {}
components:
  schemas:
    HTTPValidationError:
      properties:
        detail:
          items:
            $ref: '#/components/schemas/ValidationError'
          type: array
          title: Detail
      type: object
      title: HTTPValidationError
    Request:
      properties:
        email:
          type: string
          title: Email
          description: The single email address to check, such as alpha@gmail.com. Maximum 320 characters.
      type: object
      required:
      - email
      title: Request
      example:
        email: alpha@gmail.com
    Response:
      properties:
        api_version:
          type: string
          title: Api Version
          description: The version number of this checking service.
          default: 1.0.0
        email:
          type: string
          title: Email
          description: The email address that was checked, with any extra spaces removed.
        username:
          type: string
          title: Username
          description: The part of the email address written before the @ sign.
        domain:
          type: string
          title: Domain
          description: The part of the email address written after the @ sign, always shown in lowercase letters.
        quality:
          type: string
          title: Quality
          description: 'Whether the address is safe to send to: valid, risky, or invalid.'
        free:
          type: boolean
          title: Free
          description: True if the domain belongs to a free email provider such as Gmail or Yahoo.
        role:
          type: boolean
          title: Role
          description: True if the username looks like a shared mailbox such as admin or support, rather than a
            personal inbox.
      type: object
      required:
      - email
      - username
      - domain
      - quality
      - free
      - role
      title: Response
      example:
        api_version: 1.0.0
        domain: gmail.com
        email: alpha@gmail.com
        free: true
        quality: valid
        role: false
        username: alpha
    ValidationError:
      properties:
        loc:
          items:
            anyOf:
            - type: string
            - type: integer
          type: array
          title: Location
        msg:
          type: string
          title: Message
        type:
          type: string
          title: Error Type
        input:
          title: Input
        ctx:
          type: object
          title: Context
      type: object
      required:
      - loc
      - msg
      - type
      title: ValidationError
  securitySchemes:
    siwx:
      type: apiKey
      in: header
      name: SIGN-IN-WITH-X
      description: CAIP-122 wallet signature for repeat access after payment
servers:
- url: https://email-verifier.underscoredone.com
  description: Production
tags:
- name: Network
- name: Email Verification
- name: Signup Validation
- name: Mail Server
x402Version: 2
x-payment-accepts:
- scheme: exact
  network: eip155:8453
  payTo: '0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08'
  asset: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
- scheme: exact
  network: solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp
  payTo: 8ugAWAXDB8V18kiUrGZTq1oMvU3C6Fxs8hfC6rvzQT3b
  asset: EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v