{"uid":"cap_qczuMMBh-IMNamDzxB3BO","slug":"evm-transaction-by-block-index-549f968d","name":"EVM Transaction by Block Index","description":"The Nth transaction in a block — Genesis402 / UnyKorn Operator Network","url":"https://twin.unykorn.org/evm-tx-by-index?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"params":{"type":"object","properties":{"block":{"type":"string"},"chain":{"enum":["ethereum","base","polygon","arbitrum","optimism","bsc","avalanche","gnosis","linea","scroll"],"type":"string"},"index":{"type":"integer","minimum":0}}}}},"responseSchema":{"type":"json","example":{"ok":true,"type":"evm-tx-by-index","receipt":{"tx_hash":"0x<64hex>","amount_usd":0.003,"receipt_id":"g402-<16hex>"},"generated_at":"<iso8601>"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.003","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":"$0.003/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Y3XrkGClVkoB-7PMI_V4i","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.003","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Retrieves the Nth transaction from a specific block on any of ten supported EVM chains","exampleAgentPrompt":"What's the transaction at index 2 in block 19500000 on Ethereum? Pull the full tx details for that position.","exampleUseCases":[{"title":"Audit first transaction in a block","prompt":"Can you get me the very first transaction (index 0) in Ethereum block 20000000? I want to check what it was."},{"title":"Debug a known block position on Base","prompt":"Fetch the transaction at index 5 from block 15000000 on Base — I need the tx hash so I can cross-reference it."},{"title":"Inspect Arbitrum block transaction order","prompt":"Look up the 3rd transaction in Arbitrum block 180000000 for me, I'm trying to trace the ordering of txs in that block."}],"resultDescription":"Returns a JSON object with ok:true, a type field ('evm-tx-by-index'), a receipt object containing the transaction hash (tx_hash), the USD amount associated with the call (amount_usd), a receipt ID (receipt_id), and a generated_at ISO8601 timestamp.","failureModes":["Index out of range if the requested transaction index exceeds the number of transactions in the block","Invalid block identifier if the block hash or number doesn't exist on the specified chain","Unsupported chain if a chain not in the allowed enum is provided","Payment failure if the $0.003 USDC x402 payment cannot be processed","Network timeout if the target chain RPC is slow or unavailable"],"whenToPreferThis":"Use this endpoint when you need to look up a specific transaction by its ordinal position within a known block, across any of ten major EVM chains (Ethereum, Base, Polygon, Arbitrum, Optimism, BSC, Avalanche, Gnosis, Linea, Scroll). Prefer this over general blockchain explorers when building automated agents that need programmatic, pay-per-use access to positional transaction data without API key management.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-01T18:55:29.045Z","isFirstParty":false,"canonicalSlug":"evm-transaction-by-block-index-549f968d"}