{"uid":"cap_0-J66cW91tdVyHd3hu08o","slug":"synapse-email-verification-api-2bfa7ed2","name":"Synapse Email Verification API","description":"Public data and utility APIs paid per call in USDC on Base (x402). No accounts, no API keys. 174 routes: crypto/equity data, onchain reads, DNS/email/security intel, geo/weather, x402 payment diagnostics, dev utilities and more.","url":"https://anibalb.duckdns.org/x402/verify-email?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"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","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","properties":{}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"exists":true,"smtp_response":"250 2.1.5 OK"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Lc3VONqKFFo0gafn9NKvk","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Verifies whether an email address actually exists by performing an SMTP check, returning existence status and server response","exampleAgentPrompt":"Can you check whether the email address john.doe@example.com actually exists and has a live inbox?","exampleUseCases":[{"title":"Lead list email hygiene","prompt":"I have a prospecting list and want to know if sarah.jones@acme.com is a real, deliverable email address before I add her to my outreach campaign."},{"title":"Signup fraud prevention","prompt":"A user just tried to register with the email temp_user_99@mailinator.com — can you verify whether that address actually exists and has an active inbox?"},{"title":"CRM contact validation","prompt":"Before we import this batch contact, check if the email robert.smith@oldcorp.biz is still a valid, reachable inbox — give me the SMTP response too."}],"resultDescription":"A JSON object containing a boolean 'exists' field indicating whether the email address has a live inbox, and an 'smtp_response' string with the raw SMTP server response code and message (e.g. '250 2.1.5 OK').","failureModes":["Invalid or malformed email address format returns error","Greylisting or SMTP anti-spam measures may cause false negatives","Some mail servers accept all addresses regardless of validity (catch-all), producing false positives","Network timeouts if the target mail server is unreachable","Rate-limiting or blocking by aggressive mail servers"],"whenToPreferThis":"Use this endpoint when you need real-time SMTP-level email verification — going beyond simple format checks to actually probe the mail server. Ideal for lead validation, signup fraud prevention, or CRM hygiene. Preferred over format-only validators when deliverability confirmation matters. The pay-per-call x402 model means no subscription or API key setup required.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T18:41:44.244Z","isFirstParty":false,"canonicalSlug":"synapse-email-verification-api-2bfa7ed2"}