{"uid":"cap_baiYu3mYiYQU72m7u8D7t","slug":"plainchain-v1-fact-blockchain-fact-of-the-day-4753832a","name":"Plainchain /v1/fact — Blockchain Fact of the Day","description":"Gas, balances, token data, address type, approvals, transaction decoding, x402 receipt verification and verifiable randomness on Base, Arbitrum, Ethereum and Optimism. No API key: pay $0.001-$0.01 per call in USDC on Base via x402.","url":"https://plainchain.appin60.com/v1/fact?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","properties":{"required":{"type":"string"},"properties":{"type":"string"}}},"responseSchema":{"type":"json","example":{"of":29,"fact":"On 22 May 2010 Laszlo Hanyecz paid 10,000 BTC for two pizzas...","block":36581662,"chain":"Base","index":1}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001042","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":"$0.001042/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001042","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001042","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_l-u-oL28Q2hOMhMPbwwYW","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001042","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns a rotating crypto/blockchain historical fact along with a block number, chain name, and index, served pay-per-call via x402 on Base","exampleAgentPrompt":"Give me one of those Plainchain blockchain history facts — the kind that shows a famous crypto moment with its block number and chain.","exampleUseCases":[{"title":"Crypto trivia for daily newsletter","prompt":"Pull me a blockchain history fact I can drop into today's crypto newsletter — something like the Bitcoin pizza story with the block number it happened near."},{"title":"Icebreaker fact for Web3 community bot","prompt":"I want to post a daily 'on this day in crypto' fact to our Discord — can you fetch me one of those Plainchain blockchain facts with the chain and block it references?"},{"title":"Educational snippet for onboarding flow","prompt":"Grab me an interesting blockchain history fact to show new users during our app's onboarding screen — something short, memorable, and tied to a real block on Base or Ethereum."}],"resultDescription":"A JSON object containing the total number of facts ('of'), the fact text itself ('fact'), a block number ('block'), the chain name ('chain'), and a fact index ('index'). Example: {\"of\":29,\"fact\":\"On 22 May 2010 Laszlo Hanyecz paid 10,000 BTC for two pizzas...\",\"block\":36581662,\"chain\":\"Base\",\"index\":1}","failureModes":["Payment not provided or insufficient USDC via x402 — returns 402 Payment Required","Malformed x402 payment header — authentication failure","Service temporarily unavailable — 503 or timeout","No facts available — edge case returning empty or null payload"],"whenToPreferThis":"Choose this endpoint when you want a pre-curated, human-readable blockchain history fact without needing to query chain data yourself. It's ideal for content generation, trivia bots, newsletters, or onboarding UX where you need an engaging crypto fact tied to a real block number. Prefer over raw chain data endpoints when you need narrative content rather than raw on-chain values.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-14T06:35:08.460Z","isFirstParty":false,"canonicalSlug":"plainchain-v1-fact-blockchain-fact-of-the-day-4753832a"}