Writing Algorithms

The QuantConnect API Reference is a comprehensive technical document that details every class, method, property, and event available in the LEAN algorithmic trading framework. It serves as the definitive source for understanding how to interact with LEAN, helping you quickly look up syntax and explore available features. The LEAN engine is written in C#, but you can create algorithms with either C# or Python since LEAN uses Python.Net to bridge between your Python code and the underlying C# engine. For your convenience, we provide an API Reference for both languages.