{"uid":"cap_eTtnOu51ps4OP9UJqe7nc","slug":"northline-doi-open-access-sample-8de6722e","name":"Northline DOI Open Access Sample","description":"Pay-per-call APIs, paid downloads and work-on-request for agents. Payment: x402 (USDC on Base, eip155:8453), no accounts or API keys. Catalog: https://206-81-14-131.sslip.io/?format=json. Agent guide: https://206-81-14-131.sslip.io/llms.txt","url":"https://206-81-14-131.sslip.io/svc/doi-open-access/sample?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":null,"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.008","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"registry","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":"$0.008/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.008","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.008","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_j39fNfHuGLNG8YNMgI8wi","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.008","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Retrieves open-access metadata and content information for a given DOI (Digital Object Identifier) via a pay-per-call API","exampleAgentPrompt":"Can you check if the paper with DOI 10.1371/journal.pone.0123456 is available open access and get me the metadata and any free PDF link?","exampleUseCases":[{"title":"Check paper availability before purchase","prompt":"Before I pay for this article, can you check if DOI 10.1038/nature12373 is available open access somewhere for free?"},{"title":"Build citation with open-access link","prompt":"I'm writing a literature review — can you pull the full metadata for DOI 10.1126/science.1245831 and tell me if there's a freely downloadable version?"},{"title":"Verify license for content reuse","prompt":"I want to reuse figures from this paper (DOI 10.1016/j.cell.2015.05.002) — can you check what open access license it's under and where I can get the full text?"}],"resultDescription":"Returns open-access availability status, bibliographic metadata (title, authors, journal, publication date), license type, and direct URL to free full-text or PDF if available for the given DOI.","failureModes":["DOI not found or not indexed — returns empty or error response","DOI exists but has no open access version — returns metadata with no free URL","Malformed DOI input — returns validation error","External resolver unavailable — network timeout or upstream error","Rate limiting or payment failure — x402 payment rejected or insufficient funds"],"whenToPreferThis":"Use this endpoint when you need to check open-access availability and retrieve metadata for a specific DOI without requiring an API key or subscription. Ideal for one-off or low-volume lookups where pay-per-call pricing ($0.008 USDC) is more economical than a subscription. Prefer this over Unpaywall or Crossref direct calls when you need a frictionless, no-account pay-per-call integration in an agent workflow.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T12:38:44.212Z","isFirstParty":false,"canonicalSlug":"northline-doi-open-access-sample-8de6722e"}