{"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"}]}