Websocket

📡 Subscribing to the Symbol Prices WebSocket

This section explains how to connect to the symbol prices WebSocket API and subscribe to receive real-time updates for specific trading pairs.

🧠

Note:
The code examples in this guide are written using Node.js with TypeScript and assume you're using the socket.io-client library.

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✅ Goal

Allow your application to receive live updates for assets such as BTCUSDT through a reliable WebSocket connection.

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🚀 Step 1: Install the dependency

Make sure the socket.io-client package is installed:

bash

npm install socket.io-client

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🔌 Step 2: Establishing the WebSocket connection

TypeScript

import { io, Socket } from 'socket.io-client';

this.socket = io('https://symbol-prices-api.mybroker.dev/symbol-prices', {
  autoConnect: true,                  // Automatically connects upon initialization
  reconnection: true,                 // Enables reconnection attempts
  reconnectionDelay: 5000,           // Initial delay between attempts (5s)
  reconnectionAttempts: 10,          // Retry up to 10 times
  reconnectionDelayMax: 10000,       // Max delay between attempts (10s)
  transports: ['websocket'],         // Use only WebSocket transport
});

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🔗 Step 3: Connecting and subscribing to symbols

Once connected, we emit subscription events to start receiving price updates.

Typescript

this.socket.on('connect', () => {
  this.logger.log('Symbol WS connected');

  this.socket.emit('last-symbol-price', 'default:BTCUSDT' });
});

💡

Tip: Replace 'BTCUSDT' with the symbols you want to track. You can subscribe to multiple pairs inside the for loops.

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⚠️ Step 4: Handling disconnections and errors

Typescript

this.socket.on('disconnect', () => {
  this.logger.warn('WS disconnected');
});

this.socket.on('connect_error', (err) => {
  this.logger.warn('WS connect error', err);
});

this.socket.on('connect_timeout', (timeout) => {
  this.logger.warn('WS timeout', timeout);
});

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📥 Step 5: Receiving price updates

Use the message event to handle incoming data from the server:

TypeScript

this.socket.on('message', (payload: WsMessagePayload) => {
  if (payload.event !== 'symbol.price.update') return;

  this.updateSymbolPrice({
    price: payload.data.closePrice,
    time: payload.data.time,
    symbol: payload.data.pair,
    slot: payload.data.slot,
  });
});

📘

The payload includes:

• pair: the asset symbol (e.g., BTCUSDT)
• closePrice: the latest closing price
• time: the timestamp of the update
• slot: the subscription slot identifier

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✅ Summary

Following these steps, you’ll have a functional integration with the symbol prices WebSocket. Make sure to handle reconnections and validate incoming messages to keep your system robust and up-to-date.