js13k2018 Entry
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js13kgames.com Game Server

Game server for the js13kGames Competition.


Download the skeleton. Extract the files and install the third party libraries with npm.

npm install


You can run the server locally with the following command:

npm start

You can reach the test server at http://localhost:3000

Code structure

All your code must be in the public folder. Put your server side code into the server.js file. The shared.js file is loaded at the begining of the server.js file. You can also use this code on the client side.

Deploy to Heroku

  1. Push your files to your GitHub repository
  2. Create new WebApp on heroku
  3. Add Heroku Postgres add-on (optional)
  4. Connect your WebApp with the GitHub repository
  5. Deploy your code

Submit your entry

  1. Zip all files in the public folder.
  2. Submit your entry on the js13kgames.com site.
  3. Add contact@js13kgames.com games as collaborator to your Heroku WebApp.

Server category rules

  • Sandbox server

  • Package size still below 13 kB

    • Game package will contain all the game code and assets, for the client and the server.
  • Sandboxed environment

    • Your game will run in a node.js based sandbox environment. That means you will not really use node. You cannot require modules and your own modules shipped by your 13k pack.
  • Do not leak the sandbox

    • This is not a hacking competition. This is a way to help the competition admins, the site persistence, and you. Do not touch the procfile and the skeleton code.
  • Socket.io client lib

    • You can use it. Simply add <script src="/socket.io/socket.io.js"></script> to your HTML and that will be loaded. No server configuration will be needed. The sandbox already did it.
  • Can I test the sandbox before submitting?

  • Is there any example? How do I develop my game using the sandbox server?

    • There's a simple "Rock, Paper, Scissors" example in the public folder.
  • I have more questions!


  • Can I minify the server side code?

    • Yes, but you have to keep the readable code also.
  • Can I add more npm packages?

    • Yes, but you cannot use them in your game code.
  • What files count in the 13kb limit?

    • All files in the public folder.
  • Can I deploy new code after I submited the entry?

    • Yes, but you have to resubmit your entry on the site also.
  • Can I modify the procfile or the skeleton code?

    • No