{"uid":"cap_mEDkXcuqLhGy23TNabpN9","slug":"api-direct-substack-publication-lookup-4eded6ce","name":"API Direct – Substack Publication Lookup","description":"Get a Substack publication by subdomain, custom domain, URL or ID.","url":"https://x402.apidirect.io/v1/substack/publication?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","required":[],"properties":{"publication":{"type":"string","maxLength":500,"description":"Publication subdomain (lenny), host (lenny.substack.com, www.lennysnewsletter.com) or any URL on it (max 500 characters). Provide either publication or publication_id."},"publication_id":{"type":"string","description":"Numeric publication ID, as returned in publication_id. Provide either publication or publication_id."}}}},"additionalProperties":false}}},"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_1CD0zqvQ7iImnGiVjjRHb","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":"Retrieve detailed metadata about a Substack publication by its subdomain, custom domain, full URL, or numeric publication ID.","exampleAgentPrompt":"Can you look up the Substack publication details for lenny.substack.com and tell me its publication ID and any other metadata you get back?","exampleUseCases":[{"title":"Resolve custom domain to publication ID","prompt":"I have a newsletter at www.lennysnewsletter.com — can you find its Substack publication ID so I can use it in other API calls?"},{"title":"Verify a Substack newsletter exists","prompt":"Can you check whether there's actually a Substack publication at the subdomain 'stratechery' and pull back whatever details are available?"},{"title":"Enrich newsletter data from a URL","prompt":"I found a Substack post at https://every.to/chain-of-thought — can you look up the publication behind that URL and get me the publication name and ID?"}],"resultDescription":"Returns structured metadata about the matched Substack publication, including its publication ID, name, subdomain, custom domain (if any), and other profile information such as description, author details, and subscriber-related fields.","failureModes":["Publication not found for the given subdomain or domain — returns an error or empty result","Invalid or malformed URL/subdomain input — may return a validation error","Numeric publication_id does not correspond to any known publication — returns not-found error","Neither publication nor publication_id provided — request rejected due to missing required parameter","Rate limiting or payment failure (x402 payment not processed) — returns 402 Payment Required"],"whenToPreferThis":"Use this endpoint when you need to resolve a Substack newsletter's identity — converting a subdomain, custom domain, URL, or numeric ID into full publication metadata. It is the right choice when you have a partial identifier (e.g. just a domain from a link) and need the canonical publication ID for use in downstream Substack API calls, or when you want to verify that a given Substack publication exists and retrieve its profile details.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T19:06:59.040Z","isFirstParty":false,"canonicalSlug":"api-direct-substack-publication-lookup-4eded6ce"}