The 12 Best Entity Component Systems for C++

Build your games with more scalability, organization, performance, and flexibility.

The Entity Component System (ECS) pattern is widely used in game development and modular logic applications. It separates data (components), behavior (systems), and entities (IDs).

Its structure can be summarized as:

• Entity: just an ID (e.g., Player = 1)
• Component: pure data (e.g., Position, Velocity, Health)
• System: logic that operates on entities with certain components (e.g., physics system uses Position and Velocity)

Advantages:

• Performance: cache-friendly, contiguous memory access
• Flexibility: add/remove behaviors without inheritance or conditionals
• Scalability: easy to manage hundreds/thousands of entities
• Organization: clear separation of data and logic

Simple example:

struct Position { float x, y; };
struct Velocity { float dx, dy; };

for (auto entity : entities_with<Position, Velocity>()) {
    entity.Position.x += entity.Velocity.dx;
    entity.Position.y += entity.Velocity.dy;
}

Common use cases:

• Physics simulations
• Particle systems
• Entity-based AI

Below is a list of the 12 best ECS libraries in C++, including descriptions, pros and cons, real project usage, and GitHub links.

01. ecs.hpp

Single-header ECS library, written in C++14. Extremely simple to integrate and use.

Pros:

• Simple and lightweight
• Easy integration
• No external dependencies

Cons:

• Lacks advanced features
• No multithreading or cache optimizations

Known uses: Educational projects and small indie games

02. ecst

Experimental ECS fully based on C++14, focused on performance and compile-time parallelism.

Pros:

• Automatic parallelism
• Heavy metaprogramming
• Compile-time optimizations

Cons:

• Complex to use
• Sparse documentation
• Not beginner-friendly

Known uses: Academic performance demos and benchmarks

03. EntityFu

Simple and efficient ECS focused on speed.

Pros:

• Very fast
• Clean, readable code
• Good for learning

Cons:

• Inactive project
• Few examples and scarce documentation

Known uses: Educational games and prototypes

04. EntityPlus

C++14 ECS with a modular approach, ideal for mid-sized games.

Pros:

• Clear structure
• Modern design
• Easy to extend

Cons:

• Low adoption
• No public benchmarks

Known uses: Indie games and personal experiments

05. entityx

Mature and widely used ECS.

Pros:

• Broad adoption
• Well-tested and documented
• Easy to use with event support

Cons:

• Not the fastest
• Few recent updates

Known uses:

• Cryptark (Alientrap)
• Several indie games and custom engines

06. entt

One of the most popular and fastest ECS libraries. Written in C++17.

Pros:

• Extremely fast and optimized
• Supports multithreading, snapshots, events
• Used in real engines

Cons:

• Steeper learning curve
• Requires at least C++17

Known uses:

• Open 3D Engine (Amazon)
• The Machinery Engine
• Many custom engines

07. gaia-ecs

Archetype-based ECS, highly optimized and modern.

Pros:

• Excellent cache locality
• High performance
• Minimalist design

Cons:

• API still maturing
• Small community

Known uses: Custom engines and experimentation

08. ginseng

Game-oriented ECS, simple and inspired by practical usage.

Pros:

• Clear interface
• Easy to understand and apply
• C++11 compatible

Cons:

• No support for advanced features
• Low visibility project

Known uses: Game prototyping

09. goomy

Extremely small and experimental ECS.

Pros:

• Minimalist code
• Ideal for studying ECS pattern

Cons:

• Not production-ready
• Lacks essential features

Known uses: Research and learning

10. kengine

Full game engine with integrated ECS architecture.

Pros:

• Includes tools beyond ECS (rendering, scripting, etc.)
• Highly customizable ECS
• Modular

Cons:

• High complexity
• Sparse external documentation

Known uses: Author's own engine for C++ games

11. matter

Modern ECS with C++17/20 support, focused on elegance and performance.

Pros:

• Concise design
• Modern architecture
• Easy to integrate

Cons:

• Small community
• Documentation could be better

Known uses: Custom engine development

12. mustache

Fast, modern ECS with simple syntax.

Pros:

• Lightweight and fast
• Easy to use
• Modern C++

Cons:

• Relatively new project
• Little community feedback

Known uses: Small games and prototypes

If you're looking for:

• Performance and production: go with entt or Gaia-ECS
• Simplicity: ecs.hpp or EntityFu
• Multithreading and compile-time: ecst
• Full engine: Kengine

Bonus:

Built together with C

• Flecs - http://github.com/SanderMertens/flecs
• pico_ecs - https://github.com/empyreanx/pico_headers

Choosing the right ECS depends on your experience level, project scope, and performance needs. All listed projects are open-source and available on GitHub for exploration and contribution.