blockSubscribe – Solana

The blockSubscribe JSON-RPC method allows clients to subscribe to block notifications. This method triggers a notification whenever a new block is confirmed or finalized.

Unstable Method

This method is considered unstable and requires the validator to be started with the --rpc-pubsub-enable-block-subscription flag. Future changes to this method's format are possible.

The blockSubscribe RPC Solana method provides real-time block notifications based on specified filters. Developers can track all transactions or only those related to a specific account or program.

Supported Networks

• Mainnet

• Devnet

Parameters

Required Parameters

• filter (string | object): Defines filter criteria for the notifications:

  • string: all – Receive notifications for all blocks.

  • object: A JSON object containing:

    • mentionsAccountOrProgram: A base-58 encoded string of an account or program.

Optional Parameters

• object (optional): Configuration object containing:

  • commitment (string): Commitment level for block finality.

    • Default: finalized

  • encoding (string): Transaction encoding format.

    • Default: json

    • Supported: json, jsonParsed, base58, base64

  • transactionDetails (string): Level of transaction detail.

    • Default: full

    • Supported: full, accounts, signatures, none

  • maxSupportedTransactionVersion (number): The maximum transaction version to return.

  • showRewards (bool): Include block rewards.

    • Default: true

Result

The response returns a subscription ID.

Result Format

• integer: The subscription ID.

Request Examples

API Endpoints

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

JSON-RPC Request – Subscribe to All Blocks

wss

wscat -c "wss://go.getblock.io/<ACCESS-TOKEN>/" -x '{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "blockSubscribe",
  "params": ["all"]
}'

JSON-RPC Request – Subscribe to Specific Account/Program

{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "blockSubscribe",
  "params": [
    {
      "mentionsAccountOrProgram": "LieKvPRE8XeX3Y2xVNHjKlpAScD12lYySBVQ4HqoJ5op"
    },
    {
      "commitment": "confirmed",
      "encoding": "base64",
      "showRewards": true,
      "transactionDetails": "full"
    }
  ]
}

Response

A successful request returns the subscription ID.

Example Response

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

In this response:

• result: The subscription ID.

Error Handling

Common blockSubscribe error scenarios:

• Invalid filter: Incorrect filter string or JSON object.

• Unsupported encoding: Invalid encoding type.

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

Example Error Response

{
  "jsonrpc": "2.0",
  "error": {
    "code": -32602,
    "message": "Invalid filter criteria"
  },
  "id": 1
}

Use Cases

The Solana blockSubscribe method is essential for:

• Real-time block monitoring.

• dApps requiring live transaction data.

• Blockchain explorers tracking new blocks.

• Performance analytics.

Code blockSubscribe Example – Web3 Integration

JavaScript

const WebSocket = require('ws');

const url = "Endpoint";
const payload = {
  jsonrpc: "2.0",
  id: "1",
  method: "blockSubscribe",
  params: [
    {
      mentionsAccountOrProgram: "LieKvPRE8XeX3Y2xVNHjKlpAScD12lYySBVQ4HqoJ5op"
    },
    {
      commitment: "confirmed",
      encoding: "base64",
      showRewards: true,
      transactionDetails: "full"
    }
  ]
};

const ws = new WebSocket(url);

ws.on('open', () => {
  ws.send(JSON.stringify(payload));
});

ws.on('message', (data) => {
  console.log("Block Subscription Update:", JSON.parse(data));
});

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

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

Integration with Web3

Integrating Web3 blockSubscribe into Solana's Core API allows developers to:

• Receive block notifications for all blocks or specific accounts/programs.

• Enhance real-time monitoring in blockchain applications.

Utilize transaction details for data analytics and performance insights.