League of Legends has dominated the gaming world for more than a decade, but many fans and developers alike still wonder what makes it tick behind the scenes. With its fast-paced gameplay, complex mechanics, and massive multiplayer infrastructure, Riot Games’ flagship title is a technical marvel. So, what programming language is League of Legends actually written in?
The answer isn’t just one language—it’s a sophisticated blend of several, with C++ serving as the foundation.
The Core: C++
At the heart of League of Legends lies C++, one of the most widely used languages in high-performance game development. Riot Games chose C++ for its:
- Speed and performance – Critical for real-time processing in a game where milliseconds matter.
- Memory control – Allows developers to fine-tune how resources are used, ensuring smooth gameplay across a wide range of PCs.
- Established game dev libraries – Such as DirectX and custom physics engines.
Most of the game’s logic, engine architecture, and networking code are believed to be written in C++, especially components involving gameplay mechanics, champion abilities, and AI behavior.
Supporting Languages and Technologies
Like many modern games, League of Legends isn’t powered by a single language alone. A variety of tools and systems are used to support development, content creation, and game operations.
Lua (Scripting Language)
- Riot has used Lua, a lightweight scripting language, for aspects of game scripting and modifiability.
- Lua is often used to implement champion abilities, particle effects, and other game behaviors that need to be quickly tested and adjusted by designers.
Python
- Widely used at Riot for tools development, automation, and internal testing.
- Python scripts help with building content pipelines, validating patches, and streamlining developer workflows.
JavaScript and Web Technologies
- Riot’s client interface (the launcher and lobby system) and out-of-game services involve JavaScript, HTML/CSS, and React.
- The frontend for patch notes, matchmaking queues, and shop interfaces are all built with web technologies.
C# and Unity (Spin-offs and Tools)
- Some of Riot’s tools and newer games—like Legends of Runeterra—are built using C# and the Unity engine.
- In the main League ecosystem, C# is used for internal tools and UI features.
Game Engine: Riot’s Proprietary Tech
Unlike many studios that rely on commercial engines like Unreal or Unity, Riot Games developed a proprietary engine specifically for League of Legends. This custom engine has been updated and expanded over the years but continues to run core gameplay elements using C++ at its base.
This choice allows Riot to maintain full control over performance, patching, and scalability—especially important given the game’s global presence and massive player base.
Server-Side Tech
On the server side, Riot has historically relied on a combination of C++, Java, and other backend languages to manage matchmaking, player data, and real-time communication between clients.
Their infrastructure also includes:
- Custom server logic to handle game sessions.
- Database systems for player profiles, match histories, and loot.
- Cloud-based tech stacks for deployment, especially as Riot has moved toward containerized services.
Final Thoughts
So, what programming language is League of Legends written in? While C++ forms the backbone of the game, Riot leverages a full suite of languages—Lua, Python, JavaScript, and C#—to support everything from gameplay scripting to server management and tool creation.
This multi-language ecosystem reflects the complexity of modern game development—and shows how Riot’s technical decisions have enabled League to remain one of the most popular, scalable, and finely-tuned games in the world.
Written by:
Christian