# chainquery getmempoolentry

> chainquery getmempoolentry is a paid API for AI agents from x402.chainquery.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-11).

Returns mempool entry details for a specific unconfirmed Bitcoin transaction, including fees, size, and ancestor/descendant counts, via chainquery's independent Bitcoin Core full node.

## Facts

- Endpoint: GET https://x402.chainquery.com/v1/rpc/getmempoolentry?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chainquery-getmempoolentry-f160422d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_x2iAl1hU_wSXrVtsTSYxl

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability chainquery-getmempoolentry-f160422d
```

Example prompt: What are the mempool details for Bitcoin transaction b6f6991d03df0e2e04dafffcd6bc418aac66049e787a3def35d93bfd7d572792 — fees, size, and how many ancestors does it have?

## When to prefer this

Use this endpoint when you need detailed mempool metadata for a specific unconfirmed Bitcoin transaction — especially fees, fee rate, size, and ancestor/descendant package data — without needing a persistent API key. Ideal for pay-per-call use cases where you query mempool data infrequently and want to avoid subscription overhead. Prefer over public mempool APIs when you need data from an independent full node for verification or redundancy.

## Known failure modes

- Transaction not found in mempool (txid already confirmed or was never broadcast): RPC error result
- Invalid or malformed txid parameter: RPC error or 400 response
- Payment failure or insufficient USDC balance via x402: 402 Payment Required
- Malformed params JSON array: RPC parse error
- Node temporarily unavailable: 5xx error

## How this service works

chainquery Bitcoin RPC: pay-per-call Bitcoin Core over x402, no API key. Mempool details for a transaction from chainquery's independent full node: fees, size, ancestor and descendant counts. Bitcoin Core getmempoolentry.

## Output

Returns the Bitcoin Core getmempoolentry result object for the specified txid, including fee amounts (base fee, modified fee), virtual size in vBytes, transaction weight, time the tx entered the mempool, ancestor count and fees, descendant count and fees, and whether the transaction is BIP125 replaceable.

## Request schema (JSON Schema)

```json
{
 "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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "params": {
       "type": "string",
       "description": "optional: JSON-encoded array of positional RPC params"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "result": {
       "description": "getmempoolentry result"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chainquery-getmempoolentry-f160422d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.chainquery.com](https://www.zero.xyz/host/x402.chainquery.com/llms.txt)