{"uid":"cap_-2KkEMZxqrpN05rMn0Y14","slug":"httpay-xyz-d2bdc836","name":"Base Sequencer Pending Transaction Feed (Mempool Scanner)","description":"Base sequencer pending transaction feed — large pending swaps, MEV opportunities, frontrunning signals. Base uses a centralized sequencer so this shows the sequencer queue rather than a traditional mempool.","url":"https://httpay.xyz/api/mempool-scanner","method":"POST","headers":{},"bodySchema":null,"responseSchema":{"type":"json","example":{"description":"Base sequencer pending transaction feed — large pending swaps, MEV opportunities, frontrunning signals. Base uses a centralized sequencer so this shows the sequencer queue rather than a traditional mempool."}},"example":{"request":{"chain":"base","limit":10,"filter":"large_swaps"},"response":{"meta":{"x402":true,"poweredBy":"Alfred Zhang 🫡"},"chain":"Base (EIP-155:8453)","riskLevel":"LOW","timestamp":"2026-06-12T03:52:46.246Z","usefulFor":["MEV detection","frontrunning signals","pending swap monitoring","sequencer queue analysis"],"dataSource":"Base public RPC (live)","largeSwaps":[{"to":"0xfdf682f51fe81aa4898f0ae2163d8a55c127fbc7","from":"0xf55e3f3a6300cfa45581f23b708ecae6042a1a86","hash":"0x1e04cf14db9cba7b256a7bae096eef2655afb7a1fbbb626d58f44eff4431713b","valueETH":"0.030000","isDexRouter":false,"inputSelector":"0x3593564c","gasPricePremium":"0.0% above base","isSwapSignature":true}],"mevSignals":["💧 1 pending swaps detected — watch for sandwich attacks on larger trades"],"latestBlock":{"hash":"0x02266964d9ecd6d357090155134430a37dde4051dfa3562f63302220fd9e7ace","number":47223509,"timestamp":"2026-06-12T03:52:45.000Z"},"highValueTxs":[],"pendingQueue":{"totalTxCount":237,"totalValueETH":"0.0635","largeSwapCount":1,"analyzedTxCount":237,"highValueTxCount":0},"sequencerNote":"Base uses a centralized sequencer (Optimism OP Stack). There is no public mempool — transactions go directly to the sequencer. This endpoint shows the sequencer's pending block queue.","currentGasGwei":"NaN"}},"exampleRequest":{"chain":"base","limit":10,"filter":"large_swaps"},"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_ca5YjAWygJVI_PTGGv7Gb","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the Base sequencer's pending transaction queue filtered for large pending swaps, MEV opportunities, and frontrunning signals","exampleAgentPrompt":"Show me the current Base sequencer pending transaction queue — I want to see large pending swaps and any MEV sandwich or frontrunning opportunities available right now.","exampleUseCases":null,"resultDescription":"A feed of pending transactions from the Base sequencer queue, highlighting large swaps, identified MEV opportunities, and frontrunning signals with relevant transaction metadata","failureModes":["Payment not provided — returns 402 with x402 and MPP payment instructions","Sequencer queue temporarily unavailable — may return 503 or empty results","No large pending transactions currently in queue — returns empty list","Rate limiting if demo quota exceeded without payment"],"whenToPreferThis":"Use this endpoint when you need real-time visibility into the Base chain sequencer's pending transaction queue specifically for MEV, sandwich attack detection, or frontrunning signal extraction. Unlike Ethereum mainnet mempool scanners, this reflects Base's centralized sequencer queue rather than a p2p mempool.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T18:47:10.934Z","isFirstParty":false}