{"uid":"cap_5il4YewRWgd3H09x6s-SB","slug":"ip-listed-on-lashback-dnsbl-cae4720f","name":"IP Listed on Lashback DNSBL","description":"Is this IPv4 address listed on lashback (ubl.unsubscore.com)? Performs the DNSBL query (reversed octets under ubl.unsubscore.com, via Cloudflare DoH) and returns listed yes/no with the return codes and, where the list publishes one, the reason text. One list, one precise answer. $0.01 per lookup.","url":"https://ip.intel.rallylive.ca/ip/blacklist/lashback?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$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":{}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_At8FHueacy9EurKQq3KbF","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks whether an IPv4 address is listed on the Lashback Unsubscribe Blacklist (ubl.unsubscore.com) via a DNSBL lookup using Cloudflare DoH, returning listed status, return codes, and reason text.","exampleAgentPrompt":"Can you check if the IP address 203.0.113.42 is listed on the Lashback unsubscribe blacklist (ubl.unsubscore.com)?","exampleUseCases":[{"title":"Email deliverability pre-send check","prompt":"Before we send our newsletter campaign, can you check if our outbound mail server IP 198.51.100.25 is listed on the Lashback blacklist? I want to know if we're flagged and what reason code comes back."},{"title":"Spam complaint investigation","prompt":"We've had bounce complaints suggesting our IP might be blacklisted — can you check if 203.0.113.77 is listed on the Lashback UBL and tell me the return code and reason if it is?"},{"title":"Third-party sender reputation audit","prompt":"I'm vetting a new email marketing vendor whose sending IP is 192.0.2.15 — is that IP on the Lashback unsubscribe blacklist right now?"}],"resultDescription":"Returns a yes/no listing status for the queried IPv4 address on the Lashback UBL DNSBL, along with the raw DNSBL return codes and, where published by the list, a human-readable reason text explaining why the IP was listed.","failureModes":["Invalid or non-routable IPv4 address returns an error","DNS resolution failure via Cloudflare DoH returns an error","IPv6 addresses are not supported","Network timeout from Cloudflare DoH results in an error response","IP not listed returns listed=false with no reason text"],"whenToPreferThis":"Choose this endpoint when you need a fast, precise, single-list check specifically against the Lashback Unsubscribe Blacklist (ubl.unsubscore.com). It is ideal for email deliverability pipelines, spam filtering decisions, and reputation audits where Lashback listing status is specifically relevant. Prefer this over generic multi-list checkers when you need authoritative reason codes from Lashback specifically.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-12T18:47:55.826Z","isFirstParty":false,"canonicalSlug":"ip-listed-on-lashback-dnsbl-cae4720f"}