{"uid":"cap_EEoUpK3NK05SC6HbykB9U","slug":"mailcheck-domain-check-api-651ead12","name":"MailCheck Domain Check API","description":"Email address and domain checks for AI agents: syntax, MX, disposable/role/free flags, typo suggestions, SPF/DMARC/DKIM, RDAP and a deliverability grade. Pay per item with x402 (USDC on Base) or Lightning sats. No signup.","url":"https://mailcheck.toolschemaforge.workers.dev/v1/domain-check?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"],"type":"string"},"queryParams":{"type":"object","properties":{"domain":{"type":"string"},"domains":{"type":"string","description":"Comma-separated domains"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"count":{"type":"integer"},"results":{"type":"array","items":{"type":"object","required":["input","valid","grade","score","reasons"],"properties":{"dns":{"type":["object","null"],"description":"a, aaaa, mx, ns, txt records and per-type lookup status"},"mail":{"type":["object","null"],"description":"accepts_mail, null_mx, spf (parsed), dmarc (parsed), dkim (selectors found)"},"grade":{"enum":["A","B","C","D","F"],"type":"string"},"input":{"type":"string"},"score":{"type":"integer"},"valid":{"type":"boolean"},"domain":{"type":["string","null"]},"exists":{"type":"boolean"},"reasons":{"type":"array","items":{"type":"string"}},"registration":{"type":["object","null"],"description":"RDAP: registrar, created, expires, updated, statuses, nameservers, dnssec, age_days, days_to_expiry"}}}}}}}}}},"responseSchema":{"type":"json","example":{"count":1,"results":[{"mail":{"spf":{"all":"-all","present":true},"dkim":{"found":[]},"dmarc":{"policy":"reject","present":true},"null_mx":true,"accepts_mail":false},"grade":"A","input":"example.org","score":100,"valid":true,"domain":"example.org","exists":true,"reasons":["null MX: domain declares it sends/receives no mail"],"registration":{"status":"ok","created":"1995-08-31T04:00:00Z","expires":"2027-08-30T04:00:00Z","registrar":"Example Registrar"}}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_CtNpC29xpR2ZDGoSNQsff","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks one or more domains for DNS records, mail infrastructure health (SPF/DMARC/DKIM), RDAP registration data, and returns a deliverability grade","exampleAgentPrompt":"Can you check the email infrastructure for acme.com — I want to know if it has valid SPF, DMARC, and DKIM records set up, whether it accepts mail, and what deliverability grade it gets?","exampleUseCases":[{"title":"Pre-send domain deliverability audit","prompt":"Before we launch our email campaign, check deliverability for sendgrid.com and mailgun.com — I need to know their SPF and DMARC status and whether they'd get a good deliverability grade."},{"title":"Verify domain mail security posture","prompt":"Can you audit the email security setup for stripe.com? I want to see whether they have SPF, DMARC with a reject policy, and any DKIM selectors configured."},{"title":"Domain registration and expiry check","prompt":"Look up the registration details for notion.so — when was it created, when does it expire, who's the registrar, and is it in good standing?"}],"resultDescription":"Returns a JSON object with a count and an array of per-domain results. Each result includes: input domain, validity flag, deliverability grade (A–F), numeric score, reasons array, DNS records (A, AAAA, MX, NS, TXT), mail config (accepts_mail, null_mx, parsed SPF, parsed DMARC, DKIM selectors found), and RDAP registration data (registrar, created/updated/expires dates, age_days, days_to_expiry, statuses, nameservers, DNSSEC).","failureModes":["Invalid or malformed domain input returns valid:false with reasons","Domain not found in DNS returns exists:false","RDAP lookup may return null if registry does not support RDAP","DKIM selector discovery may return empty array if no selectors found","Payment failure (x402/Lightning) blocks the request before processing","Rate limiting or network timeouts from upstream DNS/RDAP resolvers"],"whenToPreferThis":"Choose this endpoint when you need comprehensive domain-level email infrastructure analysis in a single call — combining DNS, SPF/DMARC/DKIM, RDAP registration, and a deliverability grade — without signup or subscriptions, paying only per domain checked. Prefer it over general DNS lookup tools when you need the full mail security picture, or over WHOIS tools when you also need deliverability scoring.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T18:30:33.912Z","isFirstParty":false,"canonicalSlug":"mailcheck-domain-check-api-651ead12"}