slotsUpdatesSubscribe – Solana

This method is essential for real-time monitoring of slot changes and blockchain synchronization in Web3 applications.

The slotsUpdatesSubscribe RPC Solana method allows clients to subscribe to receive notifications about various slot updates from the validator.

The slotsUpdatesSubscribe method provides a WebSocket-based subscription to track slot updates, including events like slot creation, finalization, or optimistic confirmations. Developers use this to monitor block, transaction, and slot-related events efficiently.

Supported Networks

• Mainnet

• Devnet

Parameters

None: This method does not require any parameters.

Result

Returns a subscription ID, which is required for unsubscribing from notifications.

Result Format

• integer: The subscription ID needed to unsubscribe.

Request Example

API Endpoints

wss://go.getblock.io/<ACCESS-TOKEN>/

JSON-RPC Request

wss

wscat -c "wss://go.getblock.io/<ACCESS-TOKEN>/" --exec '{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "slotsUpdatesSubscribe"
}'

Response

A successful request returns a subscription ID.

Example Response

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

In this response:

• result: 0 represents the assigned subscription ID.

Notification Format

Upon slot updates, clients receive notifications containing slot details.

Example Notification

{
  "jsonrpc": "2.0",
  "method": "slotsUpdatesNotification",
  "params": {
    "result": {
      "parent": 75,
      "slot": 76,
      "timestamp": 1625081266243,
      "type": "optimisticConfirmation"
    },
    "subscription": 0
  }
}

Notification Fields

• parent (optional): The parent slot (present for "createdBank" events).

• slot: The updated slot.

• timestamp: Unix timestamp (milliseconds) of the update.

• type: Update type, which can be one of:

  • firstShredReceived

  • completed

  • createdBank

  • frozen

  • dead

  • optimisticConfirmation

  • root

• stats (optional): Present for "frozen" updates, containing transaction statistics:

  • maxTransactionsPerEntry

  • numFailedTransactions

  • numSuccessfulTransactions

  • numTransactionEntries

• err (optional): Error message, only for "dead" updates.

Error Handling

Common slotsUpdatesSubscribe error scenarios:

• Network issues: Problems with the Solana JSON-RPC API endpoints.

• Invalid WebSocket connection: Issues with maintaining a stable connection.

• Unsupported subscription: Some nodes may not support this method due to its unstable nature.

Example Error Response

{
  "jsonrpc": "2.0",
  "error": {
    "code": -32000,
    "message": "WebSocket connection error"
  },
  "id": 1
}

Use Cases

The Solana slotsUpdatesSubscribe method is essential for:

• Live blockchain monitoring.

• Tracking slot status in real-time.

• Keeping applications in sync with the latest slot updates.

• Improving dApp responsiveness by reacting to slot changes.

Code slotsUpdatesSubscribe Example – Web3 Integration

JavaScript

const WebSocket = require('ws');

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

ws.on('open', () => {
  const payload = {
    jsonrpc: "2.0",
    id: 1,
    method: "slotsUpdatesSubscribe"
  };
  ws.send(JSON.stringify(payload));
});

ws.on('message', (data) => {
  console.log("Slots Updates Notification:", JSON.parse(data));
});

ws.on('error', (error) => {
  console.error("WebSocket error:", error.message);
});

ws.on('close', () => {
  console.log("WebSocket connection closed");
});

Integration with Web3

By integrating Web3 slotsUpdatesSubscribe into Solana's Core API, developers can:

• Monitor slot progression in real-time.

• Enhance dApps with live updates.

• Improve blockchain data tracking systems.

• Track important block and transaction updates.

This method is a critical component of the Core API, allowing developers to handle block updates, transaction tracking, and API requests efficiently.