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Emulatorjs - In browser web based emulation portable to nearly any device for many retro consoles. A mix of emulators is used between Libretro and EmulatorJS.


Supported Architectures

We utilise the docker manifest for multi-platform awareness. More information is available from docker here and our announcement here.

Simply pulling should retrieve the correct image for your arch, but you can also pull specific arch images via tags.

The architectures supported by this image are:

Architecture Available Tag
x86-64 amd64-<version tag>
arm64 arm64v8-<version tag>

Application Setup

The Backend can be accessed at:

  • http://yourhost:3000/

The first thing you will need to do is click to download the default art/configs from this interface, this will setup a skeleton directory in your /data mount. From there add roms to the respective roms directories and follow the on screen instructions to add them to your web frontend running on port 80.

I understand there may be some confusion as to project naming, but when this project (linuxserver/emulatorjs) started it was meant to be a simple frontend for self hosting folks to use the at the time deobfuscated code of that ethanaobrien was working on. Since then EmulatorJS has evolved into it's own amazing project based on Libretro cores that have been highly optimized to function for web. This project mostly contains custom built libretro cores found here. So in general despite the naming of this project and the logo this is just a docker container with a web based backend for generating a useable self hosted emulation website and is in no way affiliated with EmulatorJS.

This container (outside of the profile functionality) only generates a static set of files that can be hosted on any web provider even object storage. Everything runs in the client's browser and there are no dependencies on this container. To extract/copy this website it is at the path /emulatorjs/frontend inside the container. If you are happy with the catalouge you have created and no longer want to run stuff like the IPFS backend or want to upload these files to some other hosting provider you can simply copy the contents of that directory and kill off this container. This container can also be started without IPFS once you collection is set using the environment variable -e DISABLE_IPFS=true.

Read Only Rom Mounts

Mounting in existing rom directories Read Only can be achieved by using a special root path /roms, For example for NES:

-v /path/to/nes/roms:/roms/nes:ro

The folder names for systems are: * 3do * arcade * atari2600 * atari5200 * atari7800 * colecovision * doom * gb * gba * gbc * jaguar * lynx * msx * n64 * nds * nes * ngp * odyssey2 * pce * psx * sega32x * segaCD * segaGG * segaMD * segaMS * segaSaturn * segaSG * snes * vb * vectrex * ws

Compatible and Tested Browsers

Chromium Based Browsers- This is the golden standard whether desktop or on mobile (Android) Chrome/Chromium/Brave/Edge should always be used. They have the best performance when it comes to WebAssembly.

Firefox- This will work (at reduced performance though) without tested controller support.

Safari iOS- Safari performs well and has controller support though in recent updates the amount of ram available to a single tab (~265MB) makes it impossible to run n64 emulation or anything CD based. Do not use WKWebView applications like Chrome or Firefox on iOS they will not be detected properly in the client software. Your best bet in iOS is to add the web page to your home screen from Safari and launch from there to get a full screen interface.

Edge Xbox Series X/S- This also performs well and was the basis of this project though recent console updates have knocked the ram available to a single tab from 1GB to 128MB making it impossible to run CD based games or n64.

Retroarch Menu- The Retroarch menu can be accessed using F1 on keyboard, start/select/R1/L1 at the same time on controller, or pressing the button in the top left in touch mode.

Fast Scrolling- Items in the menu can be scrolled by letter by using PgUp/PgDn on the keyboard or the R1/L1 buttons on controller. In touch mode scrolling can be sped up by touching and dragging (while holding) either up or down.

For Xbox users please click the select button a couple times after launching a game to ensure the B button does not trigger a "back" action in the browser. (official name "view button" it is the two small squares) Exiting the controller mode and back to browser controls can be triggered by holding the start button for 3 seconds. (official name "menu button" the three lines)


To help you get started creating a container from this image you can either use docker-compose or the docker cli.

    container_name: emulatorjs
      - PUID=1000
      - PGID=1000
      - TZ=Etc/UTC
      - SUBFOLDER=/ #optional
      - /path/to/config:/config
      - /path/to/data:/data
      - 3000:3000
      - 80:80
      - 4001:4001 #optional
    restart: unless-stopped

docker cli (click here for more info)

docker run -d \
  --name=emulatorjs \
  -e PUID=1000 \
  -e PGID=1000 \
  -e TZ=Etc/UTC \
  -e SUBFOLDER=/ `#optional` \
  -p 3000:3000 \
  -p 80:80 \
  -p 4001:4001 `#optional` \
  -v /path/to/config:/config \
  -v /path/to/data:/data \
  --restart unless-stopped \


Containers are configured using parameters passed at runtime (such as those above). These parameters are separated by a colon and indicate <external>:<internal> respectively. For example, -p 8080:80 would expose port 80 from inside the container to be accessible from the host's IP on port 8080 outside the container.

Ports (-p)

Parameter Function
3000 Rom/artwork management interface, used to generate/manage config files and download artwork
80 Emulation frontend containing static web files used to browse and launch games
4001 IPFS peering port, if you want to participate in the P2P network to distribute frontend artwork please forward this to the Internet

Environment Variables (-e)

Env Function
PUID=1000 for UserID - see below for explanation
PGID=1000 for GroupID - see below for explanation
TZ=Etc/UTC specify a timezone to use, see this list.
SUBFOLDER=/ Specify a subfolder for reverse proxies IE '/FOLDER/'

Volume Mappings (-v)

Volume Function
/config Path to store user profiles
/data Path to store roms/artwork

Miscellaneous Options

Parameter Function

Environment variables from files (Docker secrets)

You can set any environment variable from a file by using a special prepend FILE__.

As an example:

-e FILE__MYVAR=/run/secrets/mysecretvariable

Will set the environment variable MYVAR based on the contents of the /run/secrets/mysecretvariable file.

Umask for running applications

For all of our images we provide the ability to override the default umask settings for services started within the containers using the optional -e UMASK=022 setting. Keep in mind umask is not chmod it subtracts from permissions based on it's value it does not add. Please read up here before asking for support.

User / Group Identifiers

When using volumes (-v flags), permissions issues can arise between the host OS and the container, we avoid this issue by allowing you to specify the user PUID and group PGID.

Ensure any volume directories on the host are owned by the same user you specify and any permissions issues will vanish like magic.

In this instance PUID=1000 and PGID=1000, to find yours use id your_user as below:

id your_user

Example output:

uid=1000(your_user) gid=1000(your_user) groups=1000(your_user)

Docker Mods

Docker Mods Docker Universal Mods

We publish various Docker Mods to enable additional functionality within the containers. The list of Mods available for this image (if any) as well as universal mods that can be applied to any one of our images can be accessed via the dynamic badges above.

Support Info

  • Shell access whilst the container is running:

    docker exec -it emulatorjs /bin/bash
  • To monitor the logs of the container in realtime:

    docker logs -f emulatorjs
  • Container version number:

    docker inspect -f '{{ index .Config.Labels "build_version" }}' emulatorjs
  • Image version number:

    docker inspect -f '{{ index .Config.Labels "build_version" }}'

Updating Info

Most of our images are static, versioned, and require an image update and container recreation to update the app inside. With some exceptions (noted in the relevant, we do not recommend or support updating apps inside the container. Please consult the Application Setup section above to see if it is recommended for the image.

Below are the instructions for updating containers:

Via Docker Compose

  • Update images:

    • All images:

      docker-compose pull
    • Single image:

      docker-compose pull emulatorjs
  • Update containers:

    • All containers:

      docker-compose up -d
    • Single container:

      docker-compose up -d emulatorjs
  • You can also remove the old dangling images:

    docker image prune

Via Docker Run

  • Update the image:

    docker pull
  • Stop the running container:

    docker stop emulatorjs
  • Delete the container:

    docker rm emulatorjs
  • Recreate a new container with the same docker run parameters as instructed above (if mapped correctly to a host folder, your /config folder and settings will be preserved)

  • You can also remove the old dangling images:

    docker image prune

Image Update Notifications - Diun (Docker Image Update Notifier)


We recommend Diun for update notifications. Other tools that automatically update containers unattended are not recommended or supported.

Building locally

If you want to make local modifications to these images for development purposes or just to customize the logic:

git clone
cd docker-emulatorjs
docker build \
  --no-cache \
  --pull \
  -t .

The ARM variants can be built on x86_64 hardware using multiarch/qemu-user-static

docker run --rm --privileged multiarch/qemu-user-static:register --reset

Once registered you can define the dockerfile to use with -f Dockerfile.aarch64.


  • 28.01.24: - Skip IPFS config if DISABLE_IPFS is set as env variable.
  • 27.01.24: - Add atari5200 support.
  • 24.01.24: - Pin node back on aarch64 as well for compatibility.
  • 23.01.24: - Add logic to symlink out RO rom directories to support upgrades.
  • 14.01.24: - Update remaining cores for melonds and yabause threaded to fix audio issues.
  • 11.01.24: - Use Node 16 on x86 image to restore metadata uploads in backend, update psx core to current.
  • 07.01.24: - Update to use new Mupen64 plus core by default.
  • 06.01.24: - Update many emulators to fix audio issues and use latest codebases.
  • 29.12.23: - Rebase to Alpine 3.19, add option to launch without IPFS.
  • 09.08.23: - Rebase to Alpine 3.18, migrate to s6v3.
  • 06.07.23: - Deprecate armhf. As announced here
  • 24.11.22: - Update IPFS links for chdman.
  • 04.04.22: - Ingest pre-built chdman bins during build time.
  • 23.02.22: - Update ingestion point for emulatorjs bins.
  • 25.01.22: - Allow users to mount in existing rom directories.
  • 14.01.22: - Add profile paths and rebase to Alpine 3.15.
  • 04.01.22: - Add headers needed for Threaded emulators.
  • 29.11.21: - Add wasm mime type to NGINX.
  • 26.11.21: - Configure IPFS in a lower power mode, use homebuilt blobs for emu cores.
  • 19.11.21: - Pin retroarch version.
  • 14.11.21: - Update default cores to ingest.
  • 23.10.21: - Initial release.