# chainquery getmempooldescendants

> chainquery getmempooldescendants is a paid API for AI agents from x402.chainquery.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Returns all in-mempool descendant transactions of a given transaction using Bitcoin Core's getmempooldescendants RPC, via pay-per-call x402 micropayment.

## Facts

- Endpoint: GET https://x402.chainquery.com/v1/rpc/getmempooldescendants
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chainquery-getmempooldescendants-8892aafd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FqCmtLwVALzLqWIlBrfnw

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-getmempooldescendants-8892aafd
```

Example prompt: What are all the in-mempool descendants of Bitcoin transaction f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16? Give me the full verbose details.

## When to prefer this

Use this endpoint when you need to trace the descendant chain of an unconfirmed Bitcoin transaction in the mempool — for example, to analyze CPFP (child-pays-for-parent) relationships, assess package fees, or understand transaction dependency graphs — without setting up your own Bitcoin Core node or obtaining an API key. The x402 micropayment model means you pay $0.01 USDC per call with no subscription required.

## Known failure modes

- Invalid or malformed txid returns RPC error
- Transaction not in mempool returns error (transaction not in mempool)
- Transaction has no descendants returns empty object
- Malformed JSON in params query parameter returns parse error
- Payment not included or insufficient returns HTTP 402
- Node temporarily unavailable returns connection error

## How this service works

chainquery Bitcoin RPC: pay-per-call Bitcoin Core over x402, no API key. In-mempool descendants of a transaction from chainquery's independent full node. Bitcoin Core getmempooldescendants.

## Output

A JSON object containing the getmempooldescendants result: a map of descendant txids to their mempool entry details including fees, transaction size, weight, time, height, descendant/ancestor counts and fees, and any dependency information as reported by the chainquery independent full node.

## 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": "getmempooldescendants result"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chainquery-getmempooldescendants-8892aafd/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)