README.md

Features

• Designed for performance and highly optimized.
• Well-documented, type-stable API.
• Entity relationships as a first-class feature.
• Storage mode per component for ergonomics and SIMD,
  with support for user-defined storages.
• Extensible event system with filtering and custom event types.
• Fast batch operations for mass manipulation.
• Built-in GPU integration for maximal performance.
• No systems. Just queries. Use your own structure.
• Minimal dependencies, 100% test coverage.

Why ECS?

Entity Component Systems (ECS) offer a clean, scalable way to build individual- and agent-based models by separating agent data from behavioral logic. Agents are simply collections of components, while systems define how those components interact, making simulations modular, extensible, and efficient even with millions of heterogeneous individuals.

Ark.jl brings this architecture to Julia with a lightweight, performance-focused implementation that empowers scientific modellers to design complex and performant simulations without the need for deep software engineering expertise.

Installation

Run this to add Ark.jl to a Julia project:

using Pkg
Pkg.add("Ark")

Usage

Here is the classical Position/Velocity example that every ECS shows in the docs.

See the Manual, API docs and demos for more details.

using Ark

"""Position component"""
struct Position
    x::Float64
    y::Float64
end

"""Velocity component"""
struct Velocity
    dx::Float64
    dy::Float64
end

# Create a world with the required components
world = World(Position, Velocity)

for i in 1:1000
    # Create an entity with components
    entity = new_entity!(world, (Position(i, i * 2), Velocity(1, 1)))
end

# Time loop
for i in 1:10
    # Iterate a query (archetypes)
    for (entities, positions, velocities) in Query(world, (Position, Velocity))
        # Iterate entities in the current archetype
        @inbounds for i in eachindex(entities)
            # Get components of the current entity
            pos = positions[i]
            vel = velocities[i]
            # Update an (immutable) component
            positions[i] = Position(pos.x + vel.dx, pos.y + vel.dy)
        end
    end
end

Contributing

Contributions are welcome! If you encounter any issues, have suggestions for improvements, or would like to add new features, feel free to open an issue or submit a pull request.

Cite as

Lange, M. & Meligrana, A. (2025): Ark.jl – An archetype-based Entity Component System for Julia. DOI: 10.5281/zenodo.17512271, GitHub repository: https://github.com/ark-ecs/Ark.jl

License

Ark.jl and all its sources and documentation are distributed under the MIT license and the Apache 2.0 license, as your options.