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:
amd64-<version tag>
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.
The frontend application has been initially optimized around being used with a standard gamepad (more specifically for modern Xbox consoles that have chromium based Edge browsers). The navigation revolves around the up/down/left/right keys to browse the menus and launch games. Mobile browsers will function, just keep in mind compatibility will be reduced especially for CD based games.
It is important to note that some of the current emulators used for this frontend are obfuscated code, efforts are being made to reverse engineer it but you should know it can potentially reach out to third party services if you manually enable features like netplay (this should never happen in a stock setup). The point of this message is that on top of the de-obfuscation effort there is also effort to stop using binary blobs and shift to built from source libretro emscripten blobs, for now this web based emulation stack is the best for useability and compatibility. We are in the process to transitioning to libretro cores for emulators, currently 27/30 emulators have been replaced.
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) You will be unable to use features like save states and modify controller layouts on the emulatorjs based emulators currently as I have not determined a methodology of re-entering controller mode once you exit it. All normal game saves will function given you exit the game play screen cleanly using the B button for back this includes multi disc games for psx. Your game saves are stored in browser storage by hostname so if you make any changes to your local hosted setup (port or IP) the saves will not follow with it. For libretro based emulators you can use the button combination start+select+L+R to access the libretro menu and change settings/save or load/etc.
We know about most of the oddities like crackling sound for some emulators, rendering issues, and games unreliably auto launching to fullscreen. In general full CD games on the Xbox web browser do not seem to work due to their size if you have a chd/pbp less than 450 megs it will run. Edge on Xbox has some kind of undocumented ram limitation of about a gigabyte. Until all emulators are transitioned to libretro cores the oddities of using self hosted EmulatorJS will not be something that can or should be solved using hacky workarounds interacting with obfuscated code. Just keep in mind these are full blown machine emulators running in Javascript in a browser, do not expect bare metal performance.
Mounting in existing rom directories can be achieved by pointing to the default folder structure, IE lets say you would like to mount your NES library:
-v /path/to/nes/roms:/data/nes/roms
The folder names are:
  • 3do
  • arcade
  • atari2600
  • 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


To help you get started creating a container from this image you can either use docker-compose or the docker cli.
version: "2.1"
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 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 \


Docker images 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)

Rom/artwork management interface, used to generate/manage config files and download artwork
Emulation frontend containing static web files used to browse and launch games
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)

for UserID - see below for explanation
for GroupID - see below for explanation
specify a timezone to use, see this list.
Specify a subfolder for reverse proxies IE '/FOLDER/'

Volume Mappings (-v)

Path to store user profiles
Path to store roms/artwork

Miscellaneous Options

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__PASSWORD=/run/secrets/mysecretpassword
Will set the environment variable PASSWORD based on the contents of the /run/secrets/mysecretpassword 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 user as below:
$ id username
uid=1000(dockeruser) gid=1000(dockergroup) groups=1000(dockergroup)

Docker 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" }}'


  • 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.