eth_getBlockTransactionCountByNumber - Flashblocks

Example code for eth_getBlockTransactionCountByNumber Flashblocks method. Complete guide on how to use eth_getBlockTransactionCountByNumber Flashblocks in GetBlock Web3 documentation.

This returns the pending number of transactions in a block.

Parameters

Parameter	Type	Required	Description
block number	QUANTITY	TAG, Yes	the pending transaction

Request Example

cURL

curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
  "jsonrpc": "2.0",
  "method": "eth_getBlockTransactionCountByNumber",
  "params": [
    "pending"
  ],
  "id": "getblock.io"
}'

JavaScript (Axios)

import axios from 'axios';

const data = JSON.stringify({
  "jsonrpc": "2.0",
  "method": "eth_getBlockTransactionCountByNumber",
  "params": [
    "pending"
  ],
  "id": "getblock.io"
});

const config = {
    method: 'post',
    url: 'https://go.getblock.io/<ACCESS-TOKEN>/',
    headers: {
        'Content-Type': 'application/json'
    },
    data: data
};

axios(config)
    .then(response => console.log(JSON.stringify(response.data, null, 2)))
    .catch(error => console.log(error));

Python (Requests)

import requests
import json

url = "https://go.getblock.io/<ACCESS-TOKEN>/"

payload = json.dumps({
  "jsonrpc": "2.0",
  "method": "eth_getBlockTransactionCountByNumber",
  "params": [
    "pending"
  ],
  "id": "getblock.io"
})

headers = {
    'Content-Type': 'application/json'
}

response = requests.post(url, headers=headers, data=payload)
print(response.text)

Rust (Reqwest)

use reqwest::Client;
use serde_json::json;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();

    let payload = json!({
        "jsonrpc": "2.0",
        "method": "eth_getTransactionByHash",
        "params": [
                "0xa8f9b3c7d2e4f6a1b9c8d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c0d9e8f7a6"
        ],
        "id": "getblock.io"
});

    let response = client
        .post("https://go.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await?;

    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);

    Ok(())
}

Response Example

{
    "jsonrpc": "2.0",
    "result": "0x8b",
    "id": "getblock.io"
}

Response Parameters

Field	Type	Description
result	string	0x00...00 for preconfirmed; real hash once finalized

Use Cases

• Confirming a transaction has been received and included in a Flashblock

• Reading calldata / value of a preconfirmed transaction for follow-up processing

• Building activity feeds with sub-second latency

Error Handling

Status Code	Error Message	Cause
403	Forbidden	Missing or invalid <ACCESS-TOKEN>
-32602	Invalid params	Request parameters are missing or malformed
-32603	Internal error	Server-side error while processing the request
429	Too Many Requests	Rate limit exceeded for your plan

SDK Integration

ethers.js

import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider('https://go.getblock.io/<ACCESS-TOKEN>/');

// Generic JSON-RPC call — 'pending' returns Flashblocks-preconfirmed state:
const result = await provider.send('eth_getBlockTransactionCountByNumber', ["pending"]);
console.log(result);

viem

import { createPublicClient, http } from 'viem';

const client = createPublicClient({
    transport: http('https://go.getblock.io/<ACCESS-TOKEN>/')
});

// viem's read methods accept blockTag: 'pending' for Flashblocks-preconfirmed state:
const result = await client.request({
    method: 'eth_getBlockTransactionCountByNumber',
    params: ["pending"]
});
console.log(result);