acquireMempool - Cardano

Example code for the acquireMempool WebSocket method. Complete guide on how to use acquireMempool WebSocket in GetBlock Web3 documentation.

This method acquires a snapshot of the node's mempool. Subsequent mempool queries are answered against this snapshot until it is released or re-acquired. This protocol requires a WebSocket connection.

Parameters

This method does not require parameters.

Request

JavaScript

example.js

import WebSocket from 'ws';

const client = new WebSocket('wss://go.getblock.io/<ACCESS-TOKEN>/');

client.once('open', () => {
    client.send(JSON.stringify({"jsonrpc": "2.0", "method": "acquireMempool", "id": "getblock.io"}));
});

client.on('message', (msg) => {
    console.log(JSON.parse(msg.toString()));
    client.close();
});

Python

example.py

import asyncio
import json
import websockets

async def main():
    async with websockets.connect('wss://go.getblock.io/<ACCESS-TOKEN>/') as ws:
        await ws.send(json.dumps({"jsonrpc": "2.0", "method": "acquireMempool", "id": "getblock.io"}))
        print(json.loads(await ws.recv()))

asyncio.run(main())

Response

{
    "jsonrpc": "2.0",
    "method": "acquireMempool",
    "result": {
        "acquired": "mempool",
        "slot": 123456789
    },
    "id": "getblock.io"
}

Response Parameters

Field	Type	Description
acquired	string	Confirmation that a mempool snapshot was acquired
slot	integer	The slot at which the snapshot was taken

Use Cases

• Mempool Inspection: Take a stable snapshot before listing transactions

• Fee Monitoring: Assess pending transactions at a fixed point

• Propagation Checks: Confirm a submitted transaction reached the mempool

• Analytics: Sample mempool contents over time

Error Handling

Error Code	Message	Description
-32602	Invalid params	The request is malformed for the current protocol state
4000	Must acquire mempool	A snapshot must be acquired before this request
-32603	Internal error	The node failed to answer the mempool request