{"uid":"cap_NWXxneb9_-_zsTgCbvtha","slug":"checkpoint402-transaction-explainer-4ec74634","name":"Checkpoint402 Transaction Explainer","description":"Explains any Base or Ethereum transaction in plain English: who sent what to whom, which tokens/NFTs moved, the function called, success/failure and fee — plus the structured decoded data.","url":"https://api.checkpoint402.com/v1/tx-explain?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","required":["hash"],"properties":{"hash":{"type":"string","description":"Transaction hash (0x + 64 hex chars)"},"chain":{"enum":["base","ethereum"],"type":"string","description":"Chain (default base)"}}}},"additionalProperties":false}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.03","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":"$0.03/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.03","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.03","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_rTElsYZgoeh87Wk0mSvgA","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.03","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Fetches a human-readable explanation of a blockchain transaction given its hash on Ethereum or Base","exampleAgentPrompt":"Can you explain what this Ethereum transaction did: 0x4a7d3f2e1b9c8a56e0f1234abcd5678ef90abcd1234ef5678ab90cd1234ef5678?","exampleUseCases":[{"title":"Debugging a failed DeFi swap","prompt":"I just made a transaction on Base that I think failed — can you explain what happened with 0xabc123def456abc123def456abc123def456abc123def456abc123def456abc123?"},{"title":"Auditing an unknown incoming transfer","prompt":"Someone sent me tokens on Ethereum and I have no idea what the transaction did — can you break down 0x9f8e7d6c5b4a3f2e1d0c9b8a7f6e5d4c3b2a1f0e9d8c7b6a5f4e3d2c1b0a9f8e for me?"},{"title":"Verifying a DeFi yield transaction","prompt":"I want to understand what yield action was performed in this Base transaction: 0x1234abcd5678ef901234abcd5678ef901234abcd5678ef901234abcd5678ef90 — was it a liquidity deposit or something else?"}],"resultDescription":"A natural-language explanation of what the specified transaction did, including the action type (e.g. swap, transfer, liquidity provision), protocols involved, tokens and amounts, and any relevant DeFi or safety context.","failureModes":["Invalid or malformed transaction hash returns an error","Transaction hash not found on the specified chain returns not-found error","Unsupported chain (neither 'base' nor 'ethereum') returns validation error","Payment failure (insufficient USDC) results in HTTP 402 and no explanation returned","Network timeout on slow block explorers may delay response"],"whenToPreferThis":"Use this endpoint when you need a concise, human-readable explanation of a specific on-chain transaction by hash on Ethereum or Base. It is particularly well-suited for DeFi-related transactions where protocol context matters. Prefer it over generic block explorers when you need structured, agent-consumable output without managing API keys, and are comfortable with a per-call USDC micropayment.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-18T00:31:02.907Z","isFirstParty":false,"canonicalSlug":"checkpoint402-transaction-explainer-4ec74634"}