{"uid":"cap_b2WTApQjqojDere51MAaO","slug":"sitecheck-subdomain-takeover-monitor-ba2fde04","name":"SiteCheck Subdomain Takeover Monitor","description":"Subdomain takeover check: lists up to 10 subdomains seen in certificate transparency logs for a domain (Cert Spotter), fetches each over HTTPS, and flags pages that show a known 'unclaimed service' message (GitHub Pages, S3, Heroku, Fastly). Looks at the page text only, not DNS records, so it can miss dangling records that show no such message.","url":"https://api.fadeandco.workers.dev/api/agent-intel/subdomain-takeover-monitor?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","required":["domain"],"properties":{"domain":{"type":"string","description":"Domain such as example.org (a URL is reduced to its host)"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"note":"Page-text check only; a page that is not one of the known messages is reported OK, which is not proof the DNS record is safe. Max 10 subdomains per call.","domain":"example.org","source":"https://api.certspotter.com/v1/issuances","results":[{"host":"www.example.org","service":null,"verdict":"OK","httpStatus":200}],"checkedAt":"2026-10-23T09:35:22.841Z","checkedSubdomains":1,"possibleTakeovers":0}},"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_Caw4t_cwD8ZRo2QIixWqT","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":"Checks up to 10 subdomains (from certificate transparency logs) of a domain for known 'unclaimed service' fingerprints indicating potential subdomain takeover vulnerability","exampleAgentPrompt":"Can you check example.org for any subdomains that might be vulnerable to takeover — like unclaimed GitHub Pages, S3 buckets, or Heroku apps?","exampleUseCases":[{"title":"Pre-launch security audit","prompt":"Before we go live, can you scan acmecorp.com for any subdomains that might be sitting unclaimed on GitHub Pages, S3, Heroku, or Fastly? I want to make sure nothing can be hijacked."},{"title":"Bug bounty recon on target domain","prompt":"I'm doing a bug bounty on targetcompany.io — can you pull subdomains from certificate transparency logs and flag any that show signs of being takeover-vulnerable?"},{"title":"Ongoing brand protection monitoring","prompt":"Check mybrand.com for subdomains that could be taken over by someone registering an unclaimed service — I want to know if anything is showing a 'page not found' or unclaimed message on Heroku or GitHub Pages."}],"resultDescription":"Returns a JSON object with the domain checked, the source (Cert Spotter CT logs), a list of up to 10 subdomains each with host name, HTTP status code, detected service (e.g. GitHub Pages, S3, Heroku, Fastly, or null), and a verdict (OK or flagged as possible takeover). Also includes the timestamp of the check, total subdomains checked, and count of possible takeovers found. Note: only page-text fingerprinting is used, not DNS record inspection.","failureModes":["Domain not found in certificate transparency logs — returns empty results list","Subdomains unreachable over HTTPS — HTTP errors recorded but page text cannot be checked","Known unclaimed-service message not present even on vulnerable page — verdicted as OK (false negative)","DNS dangling records that serve no HTTP content will be missed entirely","More than 10 subdomains exist — only the first 10 from CT logs are checked","Invalid or malformed domain input — API may return an error or unexpected results"],"whenToPreferThis":"Use this endpoint when you need a quick, low-cost check of whether any subdomains of a domain are exposing known unclaimed-service fingerprints (GitHub Pages, S3, Heroku, Fastly), using real certificate transparency data. Prefer this over a full DNS audit when you want a fast page-text signal rather than comprehensive DNS record inspection. Best suited for security recon, bug bounty reconnaissance, brand protection, and pre-launch audits where speed matters and DNS-layer analysis is handled separately.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T00:34:04.151Z","isFirstParty":false,"canonicalSlug":"sitecheck-subdomain-takeover-monitor-ba2fde04"}