{"uid":"cap_pkDKc8dOw67jjw8xc1Ekb","slug":"api-direct-search-substack-posts-133b967a","name":"API Direct – Search Substack Posts","description":"Search Substack posts by keyword across every publication.","url":"https://x402.apidirect.io/v1/substack/posts?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":["query"],"properties":{"page":{"type":"integer","default":1,"maximum":101,"minimum":1,"description":"Page number for pagination (1-101). Each page returns 16-20 posts."},"query":{"type":"string","maxLength":500,"description":"Search keyword (max 500 characters)"},"language":{"type":"string","maxLength":2,"minLength":2,"description":"Two-letter language code, e.g. es, to rank posts in that language first"},"posted_ago":{"enum":["24h","7d","30d","12m"],"type":"string","description":"Only return posts from this period: 24h (past day), 7d (past week), 30d (past month), or 12m (past year). Omit for all time. Any other value returns 400."},"get_sentiment":{"type":"boolean","default":false,"description":"Set to true to add AI emotion analysis (Plutchik's Wheel) to each result. Adds +$0.001 per request to the cost. Returns emotion scores, dominant emotion, intensity, and polarity."}}}},"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_3eXxw3kN6HpjqUF3u95Yd","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":"Search Substack posts by keyword across all publications, with optional time filtering, language ranking, and AI sentiment analysis.","exampleAgentPrompt":"Search Substack for posts about 'central bank digital currency' from the past 30 days and include AI emotion analysis on the results.","exampleUseCases":[{"title":"Track brand mentions on Substack","prompt":"Search Substack for any posts mentioning 'Notion' from the past week — I want to see what newsletter writers are saying about them right now."},{"title":"Research topic with sentiment context","prompt":"Find Substack posts about 'longevity research' and turn on the sentiment analysis so I can see whether the tone is hopeful or skeptical."},{"title":"Multilingual content discovery","prompt":"Search Substack for posts about 'inteligencia artificial' and rank Spanish-language results first — show me the second page of results."}],"resultDescription":"Returns a paginated list (16–20 per page) of Substack posts matching the keyword, including post title, author, publication, publication date, excerpt, and URL. When sentiment analysis is enabled, each post also includes Plutchik's Wheel emotion scores, a dominant emotion label, intensity rating, and polarity (positive/negative/neutral).","failureModes":["Invalid posted_ago value (not 24h/7d/30d/12m) returns HTTP 400","Query exceeding 500 characters returns a validation error","Page number outside 1–101 range returns a validation error","No results found for obscure or misspelled keywords returns empty result set","Language code not exactly two letters returns a validation error","Network timeout for high-traffic queries"],"whenToPreferThis":"Use this endpoint when you need to search across all Substack publications by keyword, especially when time filtering (last 24h, week, month, or year), language preference, or AI-powered emotion/sentiment analysis are needed. Prefer this over general web search when the user specifically wants newsletter or long-form Substack content. It complements sibling endpoints for Reddit, Twitter, Instagram, and Threads searches on the same platform.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T19:07:57.245Z","isFirstParty":false,"canonicalSlug":"api-direct-search-substack-posts-133b967a"}