The 12 Best Entity Component Systems for C++

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.

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