eth_subscribe - Celo

Example code for the eth_subscribe JSON-RPC method. Complete guide on how to use eth_subscribe JSON-RPC in GetBlock Web3 documentation.

This method creates a subscription for real-time event notifications on the Celo network.

This requires a WebSocket connection and is ideal for tracking new blocks, pending transactions, or contract events with Celo's fast ~1 second block times.

Parameters

Parameter	Type	Required	Description
subscriptionType	string	Yes	Type: "newHeads", "logs", "newPendingTransactions"
options	object	No	Filter options (for "logs" type)

Request Example

cURL

cURL (wscat)

# This method requires WebSocket connection
wscat -c wss://go.getblock.io/<ACCESS-TOKEN>/

> {"jsonrpc":"2.0","method":"eth_subscribe","params":["newheads"],"id":"getblock.io"}

Javascript

JavaScript (ws)

const WebSocket = require('ws');

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

ws.on('open', () => {
    ws.send(JSON.stringify({
        jsonrpc: '2.0',
        method: 'eth_subscribe',
        params: ['newHeads'],
        id: 'getblock.io'
    }));
});

ws.on('message', (data) => {
    console.log(JSON.parse(data));
});

Python

Python (websockets)

import asyncio
import websockets
import json

async def unsubscribe():
    uri = "wss://go.getblock.io/<ACCESS-TOKEN>/"
    async with websockets.connect(uri) as ws:
        payload = {
            "jsonrpc": "2.0",
            "method": "eth_subscribe",
            "params": ["newHeads"],
            "id": "getblock.io"
        }
        await ws.send(json.dumps(payload))
        response = await ws.recv()
        print(json.loads(response))

asyncio.run(unsubscribe())

Rust

Rust (tokio-tungstenite)

use tokio_tungstenite::connect_async;
use futures_util::{SinkExt, StreamExt};
use serde_json::json;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let url = "wss://go.getblock.io/<ACCESS-TOKEN>/";
    let (mut ws, _) = connect_async(url).await?;
    
    let payload = json!({
        "jsonrpc": "2.0",
        "method": "eth_subscribe",
        "params": ["newHeads"],
        "id": "getblock.io"
    });
    
    ws.send(payload.to_string().into()).await?;
    
    if let Some(msg) = ws.next().await {
        println!("{:?}", msg?);
    }
    
    Ok(())
}

Response Example

Result

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x9cef478923ff08bf67fde6c64013158d"
}

Subscription Notification

{
  "jsonrpc": "2.0",
  "method": "eth_subscription",
  "params": {
    "subscription": "0x9cef478923ff08bf67fde6c64013158d",
    "result": {
      "number": "0x1d9f2a8",
      "hash": "0x4e3a375...",
      "parentHash": "0xb903239...",
      "timestamp": "0x65a1b2c3"
    }
  }
}

Response Definition

Field	Type	Description
result	string	Subscription ID

Use Cases

• Real-time block notifications

• Live stablecoin transfer tracking

• Pending transaction monitoring

• DeFi event streaming

Error Handling

Error Code	Description
-32602	Invalid subscription type
-32603	Internal error

SDK Integration

Ethers.js

ethers-subscribe.js

const { ethers } = require('ethers');

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

provider.on('block', (blockNumber) => {
  console.log('New block:', blockNumber);
});

Viem

viem-watchBlocks.js

import { createPublicClient, webSocket } from 'viem';
import { celo } from 'viem/chains';

const client = createPublicClient({
  chain: celo,
  transport: webSocket('wss://go.getblock.io/<ACCESS-TOKEN>/')
});

const unwatch = client.watchBlocks({
  onBlock: block => console.log('Block:', block.number)
});