QuantConnect/Lean
Lean Algorithmic Trading Engine by QuantConnect (Python, C#)
Star History
Momentum
+545
STARS · LAST 30 DAYS
18
PER DAY
#9
MOST-STARRED C#
| Window | 7 days | 30 days | 90 days |
|---|---|---|---|
| Stars gained | +126 | +545 | +1.6K |
| Per day | 18 | 18 | 18 |
| Forks gained | +26 | +105 | +263 |
Lean gained 545 stars in the last 30 days, about 18 a day, and now has 21.8K. It is about 12 years old and has averaged roughly 1.8K stars a year. It ranks #9 among C# repositories and #408 across all languages on GitHubRepo.
Trending Record
6
DAYS ON TRENDING
#209
BEST RANK
Sep 23, 2026
FIRST APPEARANCE
Active
STATUS TODAY
Lean has maintained a continuous presence across global trending indexes, peaking at #209. Below is the 30-day activity profile:
💡 Overview
Lean is an open-source project written in C#: Lean Algorithmic Trading Engine by QuantConnect (Python, C#).
Engineered for speed, consistency, and developer ease, it solves common hurdles in algorithm, algorithmic-trading-engine, c-sharp. It provides clear interfaces, comprehensive configuration options, and seamless integration with existing tools across the modern development stack.
⚡ Key Features
Optimized execution pipeline written in C# for predictable speed.
Zero-friction configuration with comprehensive sensible defaults out of the box.
Cross-platform runtime support across Linux, macOS, and Windows environments.
Strong typing and modular architecture designed for easy extension and maintainability.
Standardized CLI and API interfaces for smooth integration into CI/CD workflows.
Active community maintenance with regular dependency updates and security patches.
📥 Installation
$ git clone https://github.com/QuantConnect/Lean.git
cd Lean⚙ System Requirements
Platforms
- • macOS
- • Linux
- • Windows
Runtime & Dependencies
C# environment and standard tooling
Architecture
x86_64, ARM64 (Apple Silicon & Graviton)
🧠 How It Works
Lean coordinates its core functionality through a modular C# pipeline. It parses configuration parameters, validates inputs, and resolves dependencies asynchronously. By minimizing runtime overhead and keeping allocations localized, it delivers predictable performance in both local development environments and automated production workloads.
🎯 Production Use Cases
Production System Integration
Embed Lean into C# backend services to handle core application logic.
CI/CD Automated Pipelines
Run automated validation, builds, and integration suites during deployments.
Developer Tooling & Workflows
Accelerate developer onboarding with pre-configured project utilities.
Open Source Extension
Fork and customize internal modules under the repository's open Apache-2.0 license.
🚀 Getting Started
Install Lean using your package manager: `git clone https://github.com/QuantConnect/Lean.git`
Initialize your project workspace or configuration file for Lean.
Import Lean into your codebase or invoke it directly from your terminal.
Execute your test suite or run `Lean --help` to verify successful setup.
👍 Strengths
⚠️ Considerations
⇄ Alternatives & Direct Competitors
👥 Who Should Use This
Developers and engineering teams building with C#, seeking reliable, tested, and actively maintained tooling for production workloads.
🏆 Nearby in the Rankings
QuantConnect/Lean is currently ranked #408 by stars across every repository tracked on GitHubRepo. These are adjacent projects:
| Rank | Repository | Language | Stars | Action |
|---|---|---|---|---|
| #403 | steipete/CodexBar | Swift | ★ 22K | Compare ↗ |
| #404 | microsoft/onnxruntime | C++ | ★ 21.9K | Compare ↗ |
| #405 | desktop/desktop | TypeScript | ★ 21.9K | Compare ↗ |
| #406 | matomo-org/matomo | PHP | ★ 21.9K | Compare ↗ |
| #407 | android/nowinandroid | Kotlin | ★ 21.9K | Compare ↗ |
| #408 | QuantConnect/Lean This Project | C# | ★ 21.8K | |
| #409 | dgraph-io/dgraph | Go | ★ 21.8K | Compare ↗ |
| #410 | google/adk-python | Python | ★ 21.7K | Compare ↗ |
| #411 | netbox-community/netbox | Python | ★ 21.6K | Compare ↗ |
| #412 | vorssaint/vorssaint-utils | Swift | ★ 21.4K | Compare ↗ |
| #413 | parse-community/parse-server | JavaScript | ★ 21.4K | Compare ↗ |
Frequently Asked Questions
What does Lean do? +
Lean Algorithmic Trading Engine by QuantConnect (Python, C#)
What language is Lean written in? +
The primary language is C#. Topics include: algorithm, algorithmic-trading-engine, c-sharp, finance, forex.
Is Lean actively maintained? +
Yes, the last recorded push was on Sep 28, 2026 with 253 open issues being tracked.
How many stars does Lean have? +
Lean has 21,805 stars and 5,262 forks on GitHub.
How does Lean rank among GitHub repositories? +
With 21,805 stars, QuantConnect/Lean is ranked #408 globally across all repositories tracked on GitHubRepo and #9 among C# projects.
What license is Lean distributed under? +
The repository reports a Apache-2.0 license. Always verify the repository LICENSE file for legal terms.
