eth_subscribe - Tempo

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

Creates a real-time subscription over a WebSocket connection. Available subscription types are newHeads (new block headers), logs (matching contract events), and newPendingTransactions (mempool). Only available over WebSocket transport — use wss://go.getblock.io/<ACCESS-TOKEN>/.

WebSocket-only method. Available only over the WebSocket transport at wss://go.getblock.io/<ACCESS-TOKEN>/. Calling it over HTTP POST returns an Invalid Request error.

Parameters

Parameter

Type

Required

Description

subscriptionType

string

Yes

One of "newHeads", "logs", "newPendingTransactions"

filterObject

object

For "logs": filter with address and/or topics

Request Example

# WebSocket-only method. Use wscat (or similar) to connect first:
wscat -c 'wss://go.getblock.io/<ACCESS-TOKEN>/'

# Then send:
{"jsonrpc": "2.0", "method": "eth_subscribe", "params": ["newHeads"], "id": "getblock.io"}

import WebSocket from '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.toString()));
});

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": "eth_subscribe",
    "params": [
        "newHeads"
    ],
    "id": "getblock.io"
}))
        async for message in ws:
            print(json.loads(message))

asyncio.run(main())

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

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let (mut ws_stream, _) = connect_async("wss://go.getblock.io/<ACCESS-TOKEN>/").await?;

    let payload = json!({
        "jsonrpc": "2.0",
        "method": "eth_subscribe",
        "params": [
                "newHeads"
        ],
        "id": "getblock.io"
});
    ws_stream.send(Message::Text(payload.to_string())).await?;

    while let Some(msg) = ws_stream.next().await {
        println!("{:?}", msg?);
    }
    Ok(())
}

Response Example

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0x9cef478923ff08bf67fde6c64013158d"
}

Response Parameters

Field

Type

Description

result

string

Subscription ID, used to match incoming eth_subscription notifications and to call eth_unsubscribe

Use Cases

Real-time payment notifications for merchant integrations
Live TIP-20 transfer feeds for wallets
Streaming indexers that react to new Tempo blocks instantly

Error Handling

Status Code

Error Message

Cause

403

Forbidden

Missing or invalid <ACCESS-TOKEN>

-32602

Invalid params

Request parameters are missing or malformed

429

Too Many Requests

Rate limit exceeded for your plan

-32600

Invalid Request

eth_subscribe was called over HTTP; use a WebSocket connection instead

SDK Integration

import { ethers } from 'ethers';

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

const result = await provider.send('eth_subscribe', ["newHeads"]);
console.log(result);

import { createPublicClient, http, defineChain } from 'viem';

// Tempo is not yet in viem/chains as a built-in — define it inline.
const tempo = defineChain({
    id: 4217,
    name: 'Tempo',
    network: 'tempo',
    // Tempo has no native gas token. The `nativeCurrency` field is required by viem's
    // type system; values shown here are a no-op placeholder — actual fees are paid in TIP-20.
    nativeCurrency: { name: 'USD Placeholder', symbol: 'USD', decimals: 18 },
    rpcUrls: {
        default: { http: ['https://go.getblock.io/<ACCESS-TOKEN>/'] }
    },
    blockExplorers: { default: { name: 'Tempo Explorer', url: 'https://explore.tempo.xyz' } }
});

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

const result = await client.request({ method: 'eth_subscribe', params: ["newHeads"] });
console.log(result);

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