Base Sequencer Pending Transaction Feed (Mempool Scanner)

x402

Base Sequencer Pending Transaction Feed (Mempool Scanner) is a paid API for AI agents from httpay.xyz, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).

Returns the Base sequencer's pending transaction queue filtered for large pending swaps, MEV opportunities, and frontrunning signals

Price / call$0.01

Seller volume →—

Success—

StatusUnknown

How this service works

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.

Output

A feed of pending transactions from the Base sequencer queue, highlighting large swaps, identified MEV opportunities, and frontrunning signals with relevant transaction metadata

Example use cases

Example prompt

“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.”

Technical details

Endpoint

POSThttps://httpay.xyz/api/mempool-scanner

When to prefer

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.

Side effects

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

Input

{
  "chain": "base",
  "limit": 10,
  "filter": "large_swaps"
}

Output

{
  "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"
}

Schema · Response

{
  "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."
  }
}

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How this service works

Output

A feed of pending transactions from the Base sequencer queue, highlighting large swaps, identified MEV opportunities, and frontrunning signals with relevant transaction metadata

Technical details

Endpoint

POSThttps://httpay.xyz/api/mempool-scanner

When to prefer

Side effects

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

Input

{
  "chain": "base",
  "limit": 10,
  "filter": "large_swaps"
}

Output

{
  "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"
}

Schema · Response

{
  "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."
  }
}