{"uid":"cap_U1Qz89RFIag1MoKMgBtzL","slug":"bgp-origin-resolver-prefix-to-announcing-as-lookup-cc0bc08b","name":"BGP Origin Resolver – Prefix to Announcing AS Lookup","description":"Resolves a prefix to its announcing autonomous systems and puts that answer in context. The current state gives every origin AS seen for the prefix, the number of more specific and less specific prefixes routed alongside it, when the prefix was first and last seen, and the visibility expressed as the share of observers that see it rather than a raw count, because the raw count moves with the size of the measurement network and is not comparable across time.","url":"https://netz.halowerk.com/v1/bgp-origin","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"prefix":{"type":"string","maxLength":60,"minLength":4,"description":"IPv4 or IPv6 prefix in CIDR form, e.g. 8.8.8.0/24."},"history_days":{"type":"integer","default":30,"maximum":365,"minimum":1,"description":"How far back to look for earlier origins."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.004","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":"$0.004/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_I2UNPf1e3wXGn-5WMCkMY","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.004","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Resolves an IP prefix to its announcing autonomous systems, returning all observed origin ASes, prefix specificity counts, first/last seen timestamps, and observer-fraction visibility.","exampleAgentPrompt":"Who is announcing 185.220.101.0/24 in BGP right now? I want to know all origin ASes, how visible the prefix is across observers as a percentage, and when it was first and last seen.","exampleUseCases":[{"title":"Investigating suspicious prefix origin","prompt":"Can you look up the BGP origin for 45.142.212.0/24 and tell me which autonomous systems are announcing it, what fraction of BGP observers see it, and whether there are any more-specific routes alongside it?"},{"title":"Network due diligence before peering","prompt":"Before we set up peering with AS64496, I need to know what prefixes they're originating — start with 203.0.113.0/24 and tell me how long it's been visible and how many observers see it."},{"title":"Tracing IP block routing history","prompt":"I need to understand the routing history of 198.51.100.0/22 — which ASes have originated it, when it first appeared in BGP, and how widely it's seen across the measurement network."}],"resultDescription":"Returns the complete set of origin ASes observed for the queried prefix, a count of more-specific and less-specific prefixes in the routing table alongside it, timestamps for when the prefix was first and last seen in BGP, and visibility expressed as the fraction of RIS observers that see it — normalized to be comparable across time regardless of measurement network size.","failureModes":["Prefix not found in BGP routing table — returns empty or no-origin response","Invalid CIDR notation input — returns validation error","Prefix too specific (e.g. /32 host route) may have no routing table presence","Transient data staleness if BGP tables were recently updated","Network or API timeout for large or heavily multi-homed prefixes"],"whenToPreferThis":"Choose this endpoint when you need a contextualized BGP origin answer for a specific prefix — not just a raw AS number, but the full routing context including multi-origin situations, prefix specificity counts, historical timestamps, and normalized observer visibility. Prefer it over raw whois or RDAP lookups when routing truth (what is actually announced) matters more than registration records.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T00:35:33.568Z","isFirstParty":false}