How to Use preconfSubscribe

wss://beta.helius-rpc.com/?api-key=<API_KEY>

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "preconfSubscribe"
}

{
  "jsonrpc": "2.0",
  "result": 24040,
  "id": 1
}

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "preconfSubscribe",
  "params": [
    {
      "includeBam": true,
      "failed": false,
      "regionInclude": ["ewr", "fra"],
      "accountInclude": ["9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM"],
      "accountExclude": ["TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA"],
      "accountRequired": ["11111111111111111111111111111111"]
    }
  ]
}

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "preconfSubscribe",
  "params": [{ "includeBam": false }]
}

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "preconfSubscribe",
  "params": [{ "regionInclude": ["ewr", "fra"] }]
}

use agave_transaction_view::transaction_view::TransactionView;

// `frame` is the full binary WebSocket message
let tx_bytes = &frame[18..];
let tx = TransactionView::try_new_unsanitized(tx_bytes)?;

println!("version: {:?}", tx.version()); // Legacy, V0, or V1
println!("signature: {}", tx.signatures()[0]);
for ix in tx.instructions_iter() {
    println!("program index {}: {} bytes", ix.program_id_index, ix.data.len());
}

const WebSocket = require('ws');

const ws = new WebSocket('wss://beta.helius-rpc.com/?api-key=<API_KEY>');

ws.on('open', () => {
  ws.send(JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'preconfSubscribe' // Helius and BAM preconfirmations by default
    // Optional: txs from EWR/FRA touching a given account; Helius txs must be successful.
    // BAM ignores the status filter; region and account filters still apply.
    // params: [{ failed: false, regionInclude: ['ewr', 'fra'], accountInclude: ['9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM'] }]
    // Optional: Helius preconfirmations only
    // params: [{ includeBam: false }]
  }));

  // Keep the connection alive
  setInterval(() => ws.ping(), 30_000);
});

ws.on('message', (data, isBinary) => {
  // The subscribe acknowledgement arrives as a JSON text frame
  if (!isBinary) {
    const msg = JSON.parse(data.toString());
    if (msg.id === 1) console.log('Subscribed, ID:', msg.result);
    return;
  }

  // Notifications arrive as binary frames:
  // version (u8) | slot (u64 LE) | tx_index (u64 LE) | status (u8) | transaction bytes
  const buf = Buffer.from(data);
  const version = buf.readUInt8(0); // currently 1 — branch on this if it changes
  if (version !== 1) return; // unknown schema version; update your decoder
  const slot = buf.readBigUInt64LE(1);
  const txIndex = buf.readBigUInt64LE(9); // always 0 for BAM preconfirmations
  const status = buf.readUInt8(17); // 0 = failed, 1 = success, 2 = unknown
  const txBytes = buf.subarray(18); // transaction in Solana wire format (legacy, v0, or v1)

  console.log('Preconfirmation:', { version, slot, txIndex, status, bytes: txBytes.length });
  // Decode txBytes with a decoder that supports transaction v1 (see "Decoding the transaction")
});

ws.on('error', console.error);
ws.on('close', () => process.exit(1));

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "preconfUnsubscribe",
  "params": [24040]
}

{
  "jsonrpc": "2.0",
  "result": true,
  "id": 2
}