add-broker

name

add-broker

description

Recipe for wiring a new broker backend into DaxAlgo Terminal behind the IBrokerClient seam, alongside the existing twelve (Interactive Brokers, NinjaTrader 8, cTrader, Alpaca, Ironbeam, London Strategic Edge, Upstox, Binance, Coinbase, Bybit, Kraken, OKX). Use when the user asks to add a broker (e.g. "add Tradovate", "wire up Rithmic", "implement IBrokerClient for X"). Covers project layout, DI registration, login tile, options binding, fake vs real split, and the layering rules that must not be broken.

Add a Broker

A broker is a plug-in. The shell, repository, view-models, and strategies must stay completely untouched. If you find yourself editing MarketDataRepository, ConnectionManager, or any view-model — stop.

The app already has twelve backends: IB / NT / cTrader / Alpaca / Ironbeam (REST+WS, no SDK) / London Strategic Edge (free multi-asset data, WS+REST, no SDK) / Upstox (Indian markets, OAuth2) / Binance + Coinbase + Bybit + Kraken + OKX (keyless public crypto data), plus the always-on Simulated. Each opens a concurrent session — login no longer picks one broker. Mirror the existing patterns; for a no-SDK REST+WebSocket broker, Infrastructure/IronBeam/ and Infrastructure/Binance/ are the references (the four newer crypto venues are unverified against live).

Recipe

1. New folder under src/TradingTerminal.Infrastructure/<Broker>/ (e.g. Tradovate/).
2. Implement Real<Broker>Client : IBrokerClient — talks to the actual SDK. If the SDK is a private DLL (not on NuGet), gate the file with #if HAS_<BROKER>API and add the resolution logic to Infrastructure.csproj (mirror the HAS_IBAPI / HAS_NTAPI blocks); the client is then simply not registered when the DLL is absent. If the SDK is a NuGet package, always wire it (mirror cTrader). There is no Fake<Broker>Client — the project dropped per-broker synthetic fallbacks in favour of one always-registered Simulated broker (SimulatedBrokerClient) that covers all offline runs. Don't add a fake; if you need offline data, that's what Simulated is for.
3. Options class — <Broker>Options in Core/Configuration/. Read from appsettings.json via IOptions<XxxOptions>. ConnectAsync takes no parameters — it reads its own options.
4. DI block in Infrastructure/DependencyInjection.cs (not App.xaml.cs — that only Configures the options section):

   // gate on HAS_TRADOVATEAPI if it's a sideloaded DLL; omit the #if for a NuGet SDK
   services.AddSingleton<IBrokerClient>(sp =>
       new MeteredBrokerClient(
           ActivatorUtilities.CreateInstance<RealTradovateClient>(sp),
           sp.GetRequiredService<IBrokerApiMeter>()));
   
   services.AddSingleton<BrokerConnectionMode>(sp => new BrokerConnectionMode(
       BrokerKind.Tradovate, IsLive: true, DisplayName: "Tradovate", Description: "…"));
   

   Register alongside the existing IB/NT/cTrader/Alpaca/Simulated blocks. In App.xaml.cs, add the matching services.Configure<TradovateOptions>(ctx.Configuration.GetSection(TradovateOptions.SectionName));.
5. Login form — add a new <Broker>LoginFormViewModel : IBrokerLoginForm in src/TradingTerminal.Login/Forms/. Register it twice in LoginServiceCollectionExtensions.AddLogin (in TradingTerminal.Login) (as concrete + as IBrokerLoginForm factory delegate, mirroring the four existing forms). It pushes user-supplied creds into <Broker>Options before flipping IBrokerSelector.
6. appsettings.json — add a "Tradovate": { ... } section (no UseRealClient switch — availability is decided by SDK/DLL presence at build time).
7. Trade tape — SubscribeTradesAsync returns IAsyncEnumerable<TradeTick>. If the SDK exposes per-print trade flow with an aggressor flag, wire it (mirror IB's reqTickByTickData("AllLast") pattern). Otherwise throw NotSupportedException and add the broker to the no-trade-tape capability matrix in [[project-strategy-ideas]].
8. Instrument discovery — if the broker has a symbol search / contract universe endpoint, register an IInstrumentDiscoveryService impl so the universe tab + dropdown can resolve canonical InstrumentIds.

Hard rules

• No broker SDK types in Core or UI. Period. If EClientSocket / NTDirect / OpenClient / your new SDK leaks past Infrastructure/, the layering is broken.
• Marshal to UI dispatcher inside MarketDataRepository before touching observable collections — never inside the broker client itself, never inside a view-model.
• Surface connection drops as ConnectionState transitions via the IObservable<ConnectionState> stream. Don't crash, don't poll.
• Cancellation flows end-to-end. IAsyncEnumerable<Bar> / IAsyncEnumerable<Tick> use [EnumeratorCancellation].
• OMS stubs: implement PlaceOrderAsync / CancelOrderAsync / OrderEvents as throw new NotSupportedException() until OMS lands. Don't half-implement them.

What you DON'T touch

• MarketDataRepository — already broker-neutral.
• ConnectionManager — already routes by IBrokerSelector.
• Any view-model or .xaml outside the new login tile.
• Strategy projects.
• Core/ — never depends on anything.

Reference impls (read these first)

• src/TradingTerminal.Infrastructure/Ib/ — RealIbClient.cs (socket, EWrapper threading, HAS_IBAPI gating).
• src/TradingTerminal.Infrastructure/NinjaTrader/ — P/Invoke pattern, polling loops, HAS_NTAPI gating, history synth.
• src/TradingTerminal.Infrastructure/CTrader/ — async TLS+protobuf, OAuth, clientMsgId correlation, depth events.
• src/TradingTerminal.Infrastructure/Alpaca/ — REST + WebSocket via NuGet, eager stream auth, IEX feed pinning, multi-asset routing by Contract.SecType.

See also: broker-gotchas for the quirks of each existing backend.