eth_subscribe - Somnia

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 over WebSocket on the Somnia network for real-time event notifications. Given Somnia's ~100ms block times and high throughput, subscriptions enable efficient real-time monitoring without polling. This method requires a WebSocket connection.

This method requires a WebSocket connection (not HTTP).

Parameters

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

Subscription Types

• newHeads - Subscribe to new block headers

• logs - Subscribe to contract event logs

• newPendingTransactions - Subscribe to pending transactions

Request Example

WebSocket (JavaScript)

subscribe.js

const WebSocket = require('ws');

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

ws.on('open', () => {
  // Subscribe to new block headers
  const subscribeRequest = {
    jsonrpc: '2.0',
    id: 1,
    method: 'eth_subscribe',
    params: ['newHeads']
  };
  ws.send(JSON.stringify(subscribeRequest));
});

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

WebSocket (Python)

Subscribe to Logs (JavaScript snippet)

Response Example

Subscription Confirmation

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

New Block Notification

Response Parameters

Parameter	Type	Description
subscription	string	Subscription ID
result	object	Event data (varies by subscription type)

Use Cases

• Real-time block monitoring

• Live event tracking for dApps

• Instant transaction notifications

• Building live dashboards

• MEV and arbitrage detection

Error Handling

Error Code	Description
-32602	Invalid subscription type or filter
-32603	Internal error
Connection closed	WebSocket disconnected

SDK Integration

Ethers.js

ethers.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);
});

// Subscribe to contract events
const contract = new ethers.Contract(address, abi, provider);
contract.on('Transfer', (from, to, value) => {
  console.log('Transfer:', from, to, value);
});

Viem