Strategies

Write a QTSurfer strategy in Java, the language of the engine, or in QTScript, a compact language that becomes a Java class, and see how the two relate.

A strategy is the part of QTSurfer that decides when to buy or sell: it watches indicators on a market feed and emits signals. You can write one in two languages, and from the moment you submit it the platform treats them the same way.

Java, the language of the engine

A Java strategy is a plain Java class that extends one of the engine’s strategy base classes. It is the established route and has the full engine API: indicators configured on the builder, window listeners, state, signals with their order parameters and, when a strategy needs them, update() on every tick, logic across instruments, custom indicator classes and helper types.

• Java strategies: the model, base classes, setup, state, signals and properties.
• Java indicators: the catalogue of free and pro indicators, and how to write your own.
• Strategy patterns and strategy examples.
• Coding Java strategies: the Java authoring guide of the API.

QTScript, the newer one

QTScript is a compact language for the same strategies, in beta. You keep the part that is yours, the indicators, the windows and the signals, and leave out the ceremony of a Java class: package, imports, class, base class, property annotations and listener boilerplate. Every { } body is plain Java, so whatever the Java API offers inside a body works unchanged. It will gain syntax.

strategy "RSI reversion"

param rsiLow  = 30  "Oversold"
param rsiHigh = 70  "Overbought"

instruments */usdt

setup:
  rsi(14) window m1 {
    if (actual < rsiLow)  emitBuy(price);
    if (actual > rsiHigh) emitSell(price);
  }

• QTScript: the language, the parts of a file, windows and parameters.
• QTScript indicators: every indicator a QTScript strategy can call.

How they relate

QTScript is not a second engine. A QTScript file becomes exactly one Java class and goes through the same server-side compilation as a Java strategy, so everything that is true of a Java strategy once it is compiled is true of a QTScript one.

• The same indicators. The lines under setup: are calls on the indicator builder that a Java strategy configures in setupIndicators. The pro indicators are in both languages, and need a plan that includes them in both.
• The same data sources. A strategy reads tickers, klines or funding rates, in either language.
• The same way in. You send the raw source to POST /strategy, as text/plain, for both. There is no separate endpoint: the platform tells them apart by the text, since a QTScript source starts with strategy.
• The same runs. Once registered, a strategy is validated, backtested, swept and run live whichever language it was written in.

What QTScript leaves to Java

By design, and each one is a reason to write the strategy in Java instead:

• No update(): windows are the model, so a strategy that has to see every tick belongs in Java.
• No logic across instruments.
• No custom indicator classes, no extra fields or methods beyond what the sections declare, and no strategies with several sources.
• One class: anything that wants helper types is a Java strategy.

Switching is never a dead end: a .qtscript file is a Java class with the ceremony left out.

Where to start