As of May 1, 2026, this WebSocket method is billed based on metered data usage: 0.1 MB = 15 API credits. Learn more about WebSocket billing.

Parameters

This method does not accept any parameters

Returns

result

The result will be an RpcResponse JSON object with id equal to the subscription id (needed to unsubscribe)

Notification Format:

The notification format is the same as seen in the getAccountInfo RPC HTTP method

parent

The parent slot

root

The current root slot

slot

The newly set slot

Request

1
const web3 = require("@solana/web3.js");
2
(async () => {
3
  const solanaConnection = new web3.Connection("https://docs-demo.solana-mainnet.quiknode.pro/", {
4
    wsEndpoint: "",
5
  });
6
  solanaConnection.onSlotChange((slotInfo) =>
7
    console.log("Updated slot info: ", slotInfo)
8
  );
9
})();
10

1
const web3 = require("@solana/web3.js");
2
(async () => {
3
  const solanaConnection = new web3.Connection("https://docs-demo.solana-mainnet.quiknode.pro/", {
4
    wsEndpoint: "",
5
  });
6
  solanaConnection.onSlotChange((slotInfo) =>
7
    console.log("Updated slot info: ", slotInfo)
8
  );
9
})();
10

1
import { createSolanaRpcSubscriptions } from '@solana/kit';
2

3
const rpcSubscriptions = createSolanaRpcSubscriptions('');
4

5
async function main() {
6
    const abortController = new AbortController();
7
    
8
    const subscription = await rpcSubscriptions
9
        .slotNotifications()
10
        .subscribe({ abortSignal: abortController.signal });
11

12
    try {
13
        for await (const notification of subscription) {
14
            console.log("Updated slot info: ", notification);
15
        }
16
    } catch (e) {
17
        console.error(e);
18
    } finally {
19
        abortController.abort();
20
        console.log('Unsubscribed from slot changes');
21
    }
22
}
23

24
main();

1
import { createSolanaRpcSubscriptions } from '@solana/kit';
2

3
const rpcSubscriptions = createSolanaRpcSubscriptions('');
4

5
async function main() {
6
    const abortController = new AbortController();
7
    
8
    const subscription = await rpcSubscriptions
9
        .slotNotifications()
10
        .subscribe({ abortSignal: abortController.signal });
11

12
    try {
13
        for await (const notification of subscription) {
14
            console.log("Updated slot info: ", notification);
15
        }
16
    } catch (e) {
17
        console.error(e);
18
    } finally {
19
        abortController.abort();
20
        console.log('Unsubscribed from slot changes');
21
    }
22
}
23

24
main();

1
import solana
2
import asyncio
3
from asyncstdlib import enumerate
4
from solana.rpc.websocket_api import connect
5

6
async def main():
7
    async with connect("") as websocket:
8
        await websocket.slot_subscribe()
9
        first_resp = await websocket.recv()
10
        subscription_id = first_resp.result
11
        async for idx, msg in enumerate(websocket):
12
            print(msg)
13

14
asyncio.run(main())

1
import solana
2
import asyncio
3
from asyncstdlib import enumerate
4
from solana.rpc.websocket_api import connect
5

6
async def main():
7
    async with connect("") as websocket:
8
        await websocket.slot_subscribe()
9
        first_resp = await websocket.recv()
10
        subscription_id = first_resp.result
11
        async for idx, msg in enumerate(websocket):
12
            print(msg)
13

14
asyncio.run(main())

1
wscat -c  \ 
2
# wait for connection 
3
{"id":1,"jsonrpc":"2.0","method": "slotSubscribe" }

1
wscat -c  \ 
2
# wait for connection 
3
{"id":1,"jsonrpc":"2.0","method": "slotSubscribe" }

Response

1
{
2
  "jsonrpc": "2.0",
3
  "result": 0,
4
  "id": 1
5
}

1
{
2
  "jsonrpc": "2.0",
3
  "result": 0,
4
  "id": 1
5
}

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