{"uid":"cap_S6Nye3WNFI7m6zkbNqeCY","slug":"seneschal-top-ethereum-block-builder-query-068bd2f2","name":"Seneschal Top Ethereum Block Builder Query","description":"Single-fact: which builder has the largest slot share in the named window (24h|7d|30d)? Returns {builder, share_pct, slots_won}.","url":"https://api.seneschal.space/v1/q/top-builder","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":{"window":{"type":"string","description":"Lookback window: 24h, 7d or 30d (default 24h)."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"window":{"type":"string"},"builder":{"type":"string"},"as_of_ms":{"type":"integer"},"share_pct":{"type":"number"},"slots_won":{"type":"integer"},"total_slots":{"type":"integer"}}}}}}},"responseSchema":{"type":"json","example":{"window":"24h","builder":"titan","as_of_ms":1765532000000,"share_pct":28.6,"slots_won":412,"total_slots":1440}},"example":{"request":{"properties":"blocks_built,builder_address,market_share"},"response":{"window":"24h","builder":"0x4838b106fce9647bdf1e7877bf73ce8b0bad5f97","as_of_ms":1781630795281,"share_pct":44.49,"slots_won":3196,"total_slots":7183}},"exampleRequest":{"properties":"blocks_built,builder_address,market_share"},"tags":["x402"],"displayCostAmount":"0.001","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"settled","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_GT1c-JJB3P1gjXDo0SPp4","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the current top Ethereum mainnet block builder based on live block-building telemetry data","exampleAgentPrompt":"Who is the top Ethereum mainnet block builder right now? I want the current leader in terms of blocks built.","exampleUseCases":null,"resultDescription":"Returns data about the current top Ethereum mainnet block builder, likely including builder identity, block count or share, and related telemetry metrics used to rank builders by block production dominance.","failureModes":["No block builder data available if the telemetry feed is stale or offline","Payment failure if the $0.001 USDC x402 payment on Base is not properly submitted","Malformed input schema may cause a 400 or 422 error","Rate limiting if the endpoint is called excessively","Builder rankings may lag real-time by a few blocks due to data aggregation latency"],"whenToPreferThis":"Use this endpoint when you need real-time or near-real-time intelligence on which Ethereum block builder is currently leading block production, particularly for MEV research, competitive block-building analysis, or DeFi infrastructure monitoring. It is part of a broader Seneschal service that also offers free liquidation telemetry, making it valuable when combined with other on-chain monitoring needs.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T18:41:16.481Z","isFirstParty":false}