{"uid":"cap_ZYR22Gm_LhmG4PkcbNQ3Z","slug":"fathom-macroeconomic-data-api-related-series-lookup-0e4f16ec","name":"Fathom Macroeconomic Data API — Related Series Lookup","description":"Free macroeconomic data API powered by FRED. 816,000+ economic time series. GDP, inflation, unemployment, interest rates, and more.","url":"https://fathom-opal.vercel.app/api/related","method":"POST","headers":{},"bodySchema":{"type":"object","required":["seriesId"],"properties":{"seriesId":{"type":"string","description":"FRED series ID"}}},"responseSchema":{"type":"object","required":["source"],"properties":{"source":{"type":"string"},"series_id":{"type":"string"},"categories":{"type":"array","items":{"type":"object"}}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.04","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":"$0.04/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.04","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.04","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_mMDLh81wXbPGRB0ObChQY","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.04","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns related FRED economic time series and their categories for a given series ID","exampleAgentPrompt":"Can you find all the FRED economic series related to the US unemployment rate series UNRATE and show me what categories they belong to?","exampleUseCases":[{"title":"Expanding research on inflation indicators","prompt":"I'm researching inflation and I've been looking at the CPIAUCSL series — can you find me related FRED series so I can explore nearby indicators and see what categories they fall under?"},{"title":"Building a GDP dashboard with related metrics","prompt":"I'm putting together an economic dashboard around US GDP. Can you look up FRED series GDP and find related series so I know what other indicators to pull in alongside it?"},{"title":"Discovering interest rate data neighbors","prompt":"I'm analyzing the federal funds rate using FEDFUNDS in FRED — what other series are related to it and what economic categories do they belong to?"}],"resultDescription":"Returns a JSON object containing the source (FRED), the queried series ID, and an array of related series objects with their category metadata, enabling discovery of contextually connected economic time series.","failureModes":["Invalid or nonexistent FRED series ID returns empty or error response","Missing required seriesId field returns validation error","Downstream FRED API unavailability causes service failure","Payment not provided or insufficient USDC results in x402 payment required error"],"whenToPreferThis":"Use this endpoint when you need to discover economic time series that are related to a known FRED series ID — ideal for expanding economic research, building dashboards, or exploring the FRED taxonomy around a specific indicator. Prefer this over a general FRED series search when you already have a specific series ID and want to find its neighbors or category context.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T18:45:16.079Z","isFirstParty":false}