Bybit V5 WebSocket and REST API Integration in Delphi

Bybit is a major cryptocurrency derivatives and spot exchange, offering perpetual contracts, futures, spot trading, and options. The TsgcWSAPI_Bybit component delivers full Delphi integration with the Bybit V5 unified API — combining both WebSocket subscriptions for real-time market data and private events, and a comprehensive REST interface for trading, position management, and account queries. This article covers every available method and shows you how to connect, subscribe, and trade.

Architecture Overview

The Bybit V5 API is a unified interface that consolidates spot, linear perpetual, inverse perpetual, inverse futures, and options under a single set of endpoints. The TsgcWSAPI_Bybit component supports both channels:

• WebSocket — Real-time public market data (order books, trades, tickers, klines, liquidations) and private account events (positions, executions, orders, wallet updates).
• REST — On-demand queries and actions via oBybit.REST_API, covering market data retrieval, order placement and management, position configuration, and account information.

You select the product category through the BybitClient property, which determines the WebSocket endpoint: bybSpot, bybLinear, bybInverse, or bybPerpetual.

WebSocket API — Public Channels

Public channels provide real-time market data without authentication. Each subscription method has a corresponding unsubscribe method.

WebSocket API — Private Channels

Private channels require authentication via API key and secret. They deliver real-time updates about your account activity.

REST API — Market Data

Market data endpoints are public and do not require authentication. Access them through oBybit.REST_API.

REST API — Trading

Trading endpoints require API key authentication with appropriate permissions. These methods let you place, modify, and cancel orders.

REST API — Position Management

Position endpoints allow you to query and configure your derivative positions, including leverage, margin mode, risk limits, and stop-loss/take-profit settings.

REST API — Account

Account endpoints provide wallet balances, account configuration, and transaction logs.

Getting Started — Code Example

The following example demonstrates a complete setup: connecting to the Bybit linear perpetual endpoint, querying ticker data via REST, placing a limit order, checking the wallet balance, and subscribing to real-time trade updates via WebSocket.

var
  oClient: TsgcWebSocketClient;
  oBybit: TsgcWSAPI_Bybit;
begin
  // Create the WebSocket client
  oClient := TsgcWebSocketClient.Create(nil);
  // Create the Bybit API component
  oBybit := TsgcWSAPI_Bybit.Create(nil);
  oBybit.Client := oClient;

  // Configure API credentials
  oBybit.Bybit.ApiKey := 'your_api_key';
  oBybit.Bybit.ApiSecret := 'your_api_secret';

  // Select the product category
  oBybit.BybitClient := bybLinear;

  // Connect to the WebSocket
  oClient.Active := True;

  // REST: Get ticker information for BTCUSDT
  ShowMessage(oBybit.REST_API.GetTickers('BTCUSDT'));

  // REST: Place a limit buy order
  ShowMessage(oBybit.REST_API.PlaceLimitOrder(bbsBuy, 'BTCUSDT', 0.001, 30000));

  // REST: Get wallet balance
  ShowMessage(oBybit.REST_API.GetWalletBalance);

  // WebSocket: Subscribe to real-time trades for BTCUSDT
  oBybit.SubscribeTrade('BTCUSDT');
end;

REST vs. WebSocket

Use the REST API for on-demand operations such as placing orders, querying balances, and fetching historical data. Use WebSocket subscriptions for continuous, low-latency data streams. The two can be used simultaneously — REST calls are independent of the WebSocket connection state.

Configuration Reference

Tips and Notes

Testnet First

Always start development with Bybit.TestNet := True. The Bybit testnet provides a full simulation environment with test funds. You can create a separate testnet API key at testnet.bybit.com.

Unified V5 API

The V5 API unifies all product types under one set of endpoints. The BybitClient property determines which WebSocket stream you connect to, while the REST API automatically routes to the correct category based on your requests.

Order Convenience Methods

While PlaceOrder gives you full control over every parameter, the PlaceMarketOrder and PlaceLimitOrder convenience methods cover the most common scenarios with fewer parameters. Use the full method when you need advanced options like reduce-only, time-in-force, or conditional triggers.

Rate Limits

Bybit enforces rate limits on both REST and WebSocket endpoints. REST limits are typically per-endpoint (e.g., 10 requests per second for order placement). WebSocket subscriptions have a limit on the number of simultaneous topics. Monitor response headers and error codes to stay within bounds.