{"uid":"cap_Dp1h8GAJOGP0uNcETRQq7","slug":"polyform-crypto-fear-greed-index-91dbbb94","name":"Polyform Crypto Fear & Greed Index","description":"Pay-per-call data endpoints for AI agents. USDC on Base via x402. No account, no API key — one micropayment per call.","url":"https://api.polyform.org/v1/crypto/fear-greed?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"],"type":"string"},"queryParams":{"type":"object","properties":{}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"asOf":"2026-09-28T00:00:00.000Z","scale":"0=extreme fear, 100=extreme greed","value":45,"source":"alternative.me Crypto Fear & Greed Index","classification":"Fear"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","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":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_HNid6mINXCwbOT_jV_AIj","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the current Crypto Fear & Greed Index value (0–100) with classification label, sourced from alternative.me","exampleAgentPrompt":"What's the current crypto fear and greed index — is the market in fear or greed territory right now, and what's the exact score?","exampleUseCases":[{"title":"Pre-trade sentiment check","prompt":"Before I make any crypto trades today, what's the fear and greed index sitting at, and is the market leaning fearful or greedy?"},{"title":"DCA strategy trigger","prompt":"I only want to dollar-cost average into Bitcoin when the market is in extreme fear — what does the fear and greed index say right now?"},{"title":"Daily crypto briefing","prompt":"Give me a quick market mood check for crypto — what's the fear and greed score today and how is it classified?"}],"resultDescription":"Returns a JSON object with: the current numeric score (0–100), a classification string (e.g. 'Fear', 'Extreme Greed'), a scale description, the data source (alternative.me), and the timestamp of the reading.","failureModes":["Upstream alternative.me data unavailable — stale or missing response","Payment failure via x402 — 402 returned if USDC micropayment not completed","Rate or network issues on Base blockchain for payment verification"],"whenToPreferThis":"Choose this endpoint when you need a quick, no-auth, pay-per-call crypto sentiment score without setting up API keys or accounts. Ideal for agents that need occasional market mood checks at minimal cost ($0.002/call) via USDC micropayment on Base. Prefer over alternative.me direct if you want a machine-payable, agent-native interface with no signup friction.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T00:42:42.617Z","isFirstParty":false,"canonicalSlug":"polyform-crypto-fear-greed-index-91dbbb94"}