{"uid":"cap_BTge2JKZMkFVFAIQbOnVp","slug":"crypto-fear-greed-index-api-x402-fd524833","name":"Crypto Fear & Greed Index API (x402)","description":"USDC pay-per-call APIs for AI agents via the x402 protocol (v2, exact, Base mainnet). Send a request, receive HTTP 402 with payment requirements, pay with @x402/fetch or any x402 client, retry with the PAYMENT-SIGNATURE header.","url":"https://call402.com/api/fear-greed-index?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"limit":{"type":"integer","description":"Days of history to include, 1-30 (default 1 = latest only)"}}},"responseSchema":{"type":"json","example":{"meta":{"note":"Index updates daily at the source; values served from a 30-minute cache.","source":"alternative.me"},"index":{"date":"2026-10-21","value":74,"timestamp":1761004800,"classification":"Greed"},"history":[{"date":"2026-10-21","value":74,"timestamp":1761004800,"classification":"Greed"}],"attribution":"Crypto Fear & Greed Index by alternative.me (https://alternative.me/crypto/fear-and-greed-index/)"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","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":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_qQmwiehMzT6Na6V8mQaC6","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the current and historical Crypto Fear & Greed Index value, classification, and metadata, paid per-call via USDC over the x402 protocol.","exampleAgentPrompt":"What's the current Crypto Fear & Greed Index, and can you also pull the last 7 days of history so I can see how sentiment has been trending?","exampleUseCases":[{"title":"Daily crypto sentiment check","prompt":"What's today's Crypto Fear & Greed Index value and classification? Just the latest reading."},{"title":"Two-week sentiment trend analysis","prompt":"Pull the Crypto Fear & Greed Index for the past 14 days so I can see how market sentiment has shifted recently."},{"title":"Trading signal context","prompt":"Before I make a trade, can you check the Crypto Fear & Greed Index for the last 5 days to see if we've been in fear or greed territory?"}],"resultDescription":"Returns a JSON object containing: the current index entry (date, numeric value 0-100, Unix timestamp, and classification such as 'Fear', 'Greed', or 'Extreme Greed'), an optional history array of up to 30 daily entries in the same format, metadata about the data source and cache freshness, and an attribution string for alternative.me.","failureModes":["HTTP 402 returned on first call — client must pay 0.005 USDC via x402 protocol and retry with PAYMENT-SIGNATURE header","Invalid 'limit' value (outside 1-30 range) may cause an error or be clamped","Data is cached for up to 30 minutes so values may not reflect the very latest update","Source data (alternative.me) may be temporarily unavailable causing stale or missing responses","x402 payment facilitator downtime can block access entirely"],"whenToPreferThis":"Use this endpoint when an AI agent needs real-time or recent historical Crypto Fear & Greed Index data and is already integrated with the x402 micropayment protocol (USDC on Base mainnet). It is ideal for crypto trading assistants, market sentiment monitors, or DeFi agents that need standardized sentiment signals without managing a subscription API key. Prefer it over free alternatives when you need reliable, pay-as-you-go access with no rate-limit tiers or key management overhead.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T13:12:41.047Z","isFirstParty":false,"canonicalSlug":"crypto-fear-greed-index-api-x402-fd524833"}