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Gaming meets modern C++ - a fast and reliable entity component system (ECS) and much more

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EnTT: Gaming meets modern C++

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is a header-only, tiny and easy to use library for game programming and much more written in modern C++.
Among others, it's used in Minecraft by Mojang, the ArcGIS Runtime SDKs by Esri and the amazing Ragdoll.
If you don't see your project in the list, please open an issue, submit a PR or add the #entt tag to your topics! :+1:

Do you want to keep up with changes or do you have a question that doesn't require you to open an issue?
Join the gitter channel and the discord server, meet other users like you. The more we are, the better for everyone.
Don't forget to check the FAQs and the wiki too. Your answers may already be there.

Do you want to support

? Consider becoming a sponsor. Many thanks to these people and special thanks to:

mojang imgly

Table of Contents


The entity-component-system (also known as ECS) is an architectural pattern used mostly in game development. For further details:

This project started off as a pure entity-component system. Over time the codebase has grown as more and more classes and functionalities were added.
Here is a brief, yet incomplete list of what it offers today:

  • Statically generated integer identifiers for types (assigned either at compile-time or at runtime).
  • A
    utility for human readable resource names.
  • A minimal configuration system built using the monostate pattern.
  • An incredibly fast entity-component system based on sparse sets, with its own pay for what you use policy to adjust performance and memory usage according to the users' requirements.
  • Views and groups to iterate entities and components and allow different access patterns, from perfect SoA to fully random.
  • A lot of facilities built on top of the entity-component system to help the users and avoid reinventing the wheel (dependencies, snapshot, handles, support for reactive systems and so on).
  • The smallest and most basic implementation of a service locator ever seen.
  • A built-in, non-intrusive and macro-free runtime reflection system.
  • Static polymorphism made simple and within everyone's reach.
  • A cooperative scheduler for processes of any type.
  • All that is needed for resource management (cache, loaders, handles).
  • Delegates, signal handlers (with built-in support for collectors) and a tiny event dispatcher for immediate and delayed events to integrate in loops.
  • A general purpose event emitter as a CRTP idiom based class template.
  • And much more! Check out the wiki.

Consider this list a work in progress as well as the project. The whole API is fully documented in-code for those who are brave enough to read it.

It is also known that

is used in Minecraft.
Given that the game is available literally everywhere, I can confidently say that the library has been sufficiently tested on every platform that can come to mind.

Code Example


struct position { float x; float y; };

struct velocity { float dx; float dy; };

void update(entt::registry &registry) { auto view = registry.view();

// use a callback
view.each([](const auto &pos, auto &vel) { /* ... */ });

// use an extended callback
view.each([](const auto entity, const auto &pos, auto &vel) { /* ... */ });

// use a range-for
for(auto [entity, pos, vel]: view.each()) {
    // ...

// use forward iterators and get only the components of interest
for(auto entity: view) {
    auto &amp;vel = view.get<velocity>(entity);
    // ...


int main() { entt::registry registry;

for(auto i = 0u; i &lt; 10u; ++i) {
    const auto entity = registry.create();
    registry.emplace<position>(entity, i * 1.f, i * 1.f);
    if(i % 2 == 0) { registry.emplace<velocity>(entity, i * .1f, i * .1f); }




I started developing

for the wrong reason: my goal was to design an entity-component system to beat another well known open source solution both in terms of performance and possibly memory usage.
In the end, I did it, but it wasn't very satisfying. Actually it wasn't satisfying at all. The fastest and nothing more, fairly little indeed. When I realized it, I tried hard to keep intact the great performance of
and to add all the features I wanted to see in my own library at the same time.


is finally what I was looking for: still faster than its competitors, lower memory usage in the average case, a really good API and an amazing set of features. And even more, of course.


The proposed entity-component system is incredibly fast to iterate entities and components, this is a fact. Some compilers make a lot of optimizations because of how

works, some others aren't that good. In general, if we consider real world cases,
is somewhere between a bit and much faster than many of the other solutions around, although I couldn't check them all for obvious reasons.

If you are interested, you can compile the

test in release mode (to enable compiler optimizations, otherwise it would make little sense) by setting the
option of
, then evaluate yourself whether you're satisfied with the results or not.

Honestly I got tired of updating the README file whenever there is an improvement.
There are already a lot of projects out there that use

as a basis for comparison (this should already tell you a lot). Many of these benchmarks are completely wrong, many others are simply incomplete, good at omitting some information and using the wrong function to compare a given feature. Certainly there are also good ones but they age quickly if nobody updates them, especially when the library they are dealing with is actively developed.

The choice to use

should be based on its carefully designed API, its set of features and the general performance, not because some single benchmark shows it to be the fastest tool available.

In the future I'll likely try to get even better performance while still adding new features, mainly for fun.
If you want to contribute and/or have suggestions, feel free to make a PR or open an issue to discuss your idea.


is a header-only library. This means that including the
header is enough to include the library as a whole and use it. For those who are interested only in the entity-component system, consider to include the sole
header instead.
It's a matter of adding the following line to the top of a file:

Use the line below to include only the entity-component system instead:


Then pass the proper

argument to the compiler to add the
directory to the include paths.


To be able to use

, users must provide a full-featured compiler that supports at least C++17.
The requirements below are mandatory to compile the tests and to extract the documentation:
  • CMake
    version 3.7 or later.
  • Doxygen
    version 1.8 or later.

Alternatively, Bazel is also supported as a build system (credits to zaucy who offered to maintain it).
In the documentation below I'll still refer to

, this being the official build system of the library.


To use

from a
project, just link an existing target to the
The library offers everything you need for locating (as in
), embedding (as in
), fetching (as in
) or using it in many of the ways that you can think of and that involve
Covering all possible cases would require a treaty and not a simple README file, but I'm confident that anyone reading this section also knows what it's about and can use
from a
project without problems.

Packaging Tools

is available for some of the most known packaging tools. In particular:
  • Conan
    , the C/C++ Package Manager for Developers.

  • vcpkg
    , Microsoft VC++ Packaging Tool.
    You can download and install

    in just a few simple steps:
  $ git clone
  $ cd vcpkg
  $ ./
  $ ./vcpkg integrate install
  $ vcpkg install entt


port in
is kept up to date by Microsoft team members and community contributors.
If the version is out of date, please create an issue or pull request on the
  • Homebrew
    , the missing package manager for macOS.
    Available as a homebrew formula. Just type the following to install it:
  brew install skypjack/entt/entt
  • build2
    , build toolchain for developing and packaging C and C++ code.
    In order to use the
    package in a
    project, add the following line or a similar one to the
  depends: entt ^3.0.0

Also check that the configuration refers to a valid repository, so that the package can be found by


Both can be used with

bpkg add-repo
or added in a project
. See the official documentation for more details.

Consider this list a work in progress and help me to make it longer if you like.


also supports
(for some definition of supports at least). A suitable file called
is generated and installed in a proper directory when running
This should also make it easier to use with tools such as
or similar.


The documentation is based on doxygen. To build it:

$ cd build
$ make

The API reference will be created in HTML format within the directory

. To navigate it with your favorite browser:
$ cd build
$ your_favorite_browser docs/html/index.html

The same version is also available online for the latest release, that is the last stable tag. If you are looking for something more pleasing to the eye, consider reading the nice-looking version available on docsforge: same documentation, much more pleasant to read.
Moreover, there exists a wiki dedicated to the project where users can find all related documentation pages. <!-- @endcond TURNOFFDOXYGEN -->


To compile and run the tests,

requires googletest.
will download and compile the library before compiling anything else. In order to build the tests, set the

To build the most basic set of tests:

  • $ cd build
  • $ cmake -DENTT_BUILD_TESTING=ON ..
  • $ make
  • $ make test

Note that benchmarks are not part of this set.

EnTT in Action

is widely used in private and commercial applications. I cannot even mention most of them because of some signatures I put on some documents time ago. Fortunately, there are also people who took the time to implement open source projects based on
and did not hold back when it came to documenting them.

Here you can find an incomplete list of games, applications and articles that can be used as a reference.

If you know of other resources out there that are about

, feel free to open an issue or a PR and I'll be glad to add them to the list.


Requests for features, PRs, suggestions ad feedback are highly appreciated.

If you find you can help and want to contribute to the project with your experience or you do want to get part of the project for some other reason, feel free to contact me directly (you can find the mail in the profile).
I can't promise that each and every contribution will be accepted, but I can assure that I'll do my best to take them all as soon as possible.

If you decide to participate, please see the guidelines for contributing before to create issues or pull requests.
Take also a look at the contributors list to know who has participated so far. <!-- @endcond TURNOFFDOXYGEN -->


Code and documentation Copyright (c) 2017-2021 Michele Caini.
Colorful logo Copyright (c) 2018-2021 Richard Caseres.

Code released under the MIT license.
Documentation released under CC BY 4.0.
All logos released under CC BY-SA 4.0.

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