HTML5 and JavaScript Game Development Competition in just 13 kB

What is js13kGames?

Js13kGames is a JavaScript coding competition for HTML5 Game Developers. The fun part of the compo is the file size limit set to 13 kilobytes. The competition started at 13:00 CEST, 13th August and ended at 13:00 CEST, 13th September 2016. Theme for 2016 edition was Glitch.
Read Tuts+ Gamedev intro article, check out my blog post
and see the Rules for details, good luck and have fun!

The competition is organized by Andrzej Mazur from Enclave Games,
check out promo game Triskaidekaphobia and grab the stickers.


Mozilla Gameasy Hired
Heroic Labs Blur SkillHunt

Share the love for HTML5 games and support the js13kGames competition!
See the Contact section for more details on how to get in touch.


Jason Weathersby

Jason Weathersby

Jason Weathersby currently manages the Developer Relations group at Mozilla, evangelizing Firefox, Developer Tools, Research projects, HTML5 Gaming and all things for the Open Web. He is a proponent of HTML5, Open Web standards and Open Source and is a regular contributor to the Mozilla Hacks blog. Jason has over 25 years experience in the software development field, ranging from real time process control to business intelligence software.

@JasonWeathersby |

Elle Chen

Elle Chen

10-year experience in game industry focusing on business development, game licensing, developer relations, and Marketing. Elle has licensed a few hundred games on PC, mobile, and HTML5 in her career. She currently works at Simplaex, an innovative platform where allows game developers to monetize their player base outside of their games.

@elleycchen |

Pedro Fortuna

Pedro Fortuna

Co-founder and owner of Jscrambler where he co-leads business development, and supervises all R&D and technical activities. Inventor and co-author of three patents in the Computer Security area. Holds a degree and a MSc in Computer Science. Speaker at several IT events, related with Security and JavaScript.

@pedrofortuna |

Nicola Pacini

Nicola Pacini

Gameasy Product Owner, passionate about innovation. Dad, Husband, likes TV-series and soccer, FC Inter hard supporter.

@nipac |

Winners - Desktop


13th place Glitch by Japheth C. Balane

    31-40. Omega 13K, Short Circuit, Cycles, Space Glitchy Invaders, Glitch Drive,
    Glitch maze, Bubble Trap!, Blade Gunner, Bombslide, Neon Runner '84
    41-50. Silly Little Tanks, yoctoPets, Glitchcon, Blib Blupper, Glitch Blob,
    Ah Kin Glitch, PULSE, Popnoid, GlitchCube, Theo's Escape
    51-60. Buggy SnAkE, Cosmic Shooters, PatchNotes, 26 Games in 1, Competitive Typo Annihilation,
    Glitch in Virtual Reality, Road to Pixel, Spacetime, Save the Matrix, Super Best... Whatever

Winners - Mobile

Winners - Server


5th place HoloSim by Keith Karnage

Community Awards winners

Voted among the developers themselves.

Social Special winners

For the most popular games on the social networks.

Twitter Special

Facebook Special

Google+ Special

Super Special

Super Special is an appreciation of a given entry that was original,
unique and stood up from the others - handpicked by Andrzej Mazur.


Construct 2

3 × Construct 2 game engine personal license

Three Personal licenses for Construct 2 game engine created by Scirra.


10 × PlayCanvas Pro-5 account

Ten 6-month PlayCanvas Pro-5 accounts offering cloud-hosted, collaborative platform for building video games.


7 × WebStorm personal license

Seven personal licenses for the WebStorm JavaScript IDE created by the JetBrains team.


3 × Pusher $300 credit

Three promo codes worth $300 each for the Pusher services.

1 × Startup account

One account with Startup plan for 12 months.

Cloud9 IDE

5 × Cloud9 IDE individual subscriptions

Five different Cloud9 subscriptions: 1 year for 1st place, 6 months for 2nd and 3rd, 3 months for 4th and 5th.


3 × CodePen Pro account

Three CodePen Pro accounts with lots of cool features for 12 months.


30 × GitHub personal account

Thirty paid GitHub plans - personal accounts with unlimited private repositories for twelve months.


3 × Jscrambler license

Three Jscrambler Starter Plan licenses for three months each.

SaaS Manager

1 × SaaS Manager $1000 credit

One promo code worth $1000 for the SaaS Manager services.


There will be three different categories,
you can submit your game to any of them - it's up to you.



Full power of the hardware.



Mobile touch devices.



Node.js multiplayer.

There will also be a Twitter, Facebook and Google+ Specials just like before,
and the famous Community Awards voted among all the participants.


Desktop category

Top 15 games

  • 1st place: SaaS Manager, Making Money with HTML5 ebook, Phaser Editor, GitHub
  • 2nd-5th places: Making Money with HTML5 ebook, Phaser Editor, GitHub
  • 6th-10th places: Phaser Editor, GitHub
  • 11th-15th places: GitHub

Mobile category

Top 10 games

  • 1st place:, Complete Mobile Game Development Course, The Curious Expedition, WebStorm, GitHub
  • 2nd-5th places: Complete Mobile Game Development Course, WebStorm, The Curious Expedition, GitHub
  • 6th-7th places: WebStorm, GitHub
  • 8th-10th places: GitHub

Server category

Top 5 games

  • 1st-3rd places: Pusher, The Curious Expedition, GitHub
  • 4th-5th places: The Curious Expedition, GitHub

Social Specials

Twitter Specials (for the highest number of tweets)

  • 1st-3rd places: Construct 2, Elliot Quest
  • 4th-5th places: Elliot Quest

Facebook Specials (for the highest number of likes)

  • 1st-3rd places: CodePen, ImpactJS
  • 4th-5th places: ImpactJS

Google+ Specials (for the highest number of +1's)

  • 1st-3rd places: Jscrambler, Elliot Quest
  • 4th-5th places: Elliot Quest

Community Awards

Top 25 entries (voted among developers themselves)

  • 1st-5th places: Kendo UI, Cloud9, PlayCanvas, A Wizard's Lizard, Soul Thief
  • 6th-10th places: PlayCanvas, A Wizard's Lizard, Soul Thief
  • 11th-25th places: A Wizard's Lizard, Soul Thief


Package size below 13 kB

All your code and game assets should be smaller than or equal to 13 kilobytes (that's exactly 13,312 bytes, because of 13 x 1024) when zipped. Your .zip package should contain index.html file and when unzipped should work in the browser. Don't overcomplicate building the zip package, it should unpack on any platform without problems. You can use tools that minify JavaScript source code.

Two sources - readable and compressed

The competition is focusing on the package size, but learning from others is also very important. Please provide two sources of your game - first one should be minified and zipped to fit in the 13 kB limit (sent via the form) and the second one should be in a readable form with descriptive variable names and comments (hosted on GitHub).

No external libraries or services

You can't use any libraries, images or data files hosted on server or services that provide any type of data - for example Google Fonts are not allowed. Your game should work offline by launching the index.html file in the browser (Desktop and Mobile categories, not applicable to Server) and all the game assets should fit in the package size limit. If you manage to shrink your favorite library below 13 kilobytes including the code itself, then you can use whatever you want, just remember about the 13 kB limit.

Main theme

The main theme of the competition in 2016 is Glitch. It's highly advised to follow it in your game, because the judges will pay attention to that, but you can freely interpret the theme and implement it however you feel would be the best.

Deadline - 13th September 2016

The competition starts at 13:00 CEST, 13th August 2016 and ends at 13:00 CEST, 13th September 2016. No submissions will be accepted after the end of the competition.


You have to have the rights for every asset used in your game. Remember that the submitted games will be published and made available for everybody to see.

New content only

Do not submit any old games or demos - you have a whole month to work on something new and fresh, this should be more than enough.

Errors and browser support

Your game must work and be playable in at least two browsers: Firefox and Chrome. The more supported browsers, the better - you can get more points for that. There should be no errors - you can lose some points if your game is showing any errors in the console. If we cannot play your game, it won't be accepted.


It doesn't matter if you're working alone or with your friends, just remember that the number of prizes is fixed, so you'll have to share your trophies with your teammates.

Sending submissions

There's a special form to submit your game. Please remember that you have to provide two sources (see the Rule #2 for details) - a link to a public repository on Github and a zipped package. Participants are allowed to submit more than one game in the competition, though sending the same game as independent submissions targeting different platforms (for example separate builds for desktop and mobile) is forbidden.

Accepting submissions

Submissions will be checked manually and published after positive verification. This may take up to a couple of days, so be patient if your game is not yet online. I claim the right to reject any submission without giving a reason, although I hope I don't have to. I also have the right to update the rules of the competition at any time.

Time frames for voting, judging and announcing winners

The Social Specials contest will be held from the start of the compo on August 13th till the end of the judging on September 27th, winners will be announced on the same day right after it ends. The Community Awards voting among the participants will last for a week between September 13th and 20th, winners will be announced on September 21st. Judges will vote for the games during the two week period after the submission time ends: from September 13th till 27th, winners will be announced on September 28th.

Code of conduct

All participants and judges at js13kGames are required to agree with the following code of conduct. Organizers will enforce this code throughout the online event. We are expecting cooperation from all participants to help ensuring a safe environment for everybody.

Js13kGames is dedicated to providing a harassment-free competition experience for everyone, regardless of gender, sexual orientation, disability, physical appearance, body size, race, or religion. We do not tolerate harassment of competition participants in any form. Competition participants violating these rules may be sanctioned or expelled from the competition at the discretion of the competition organizers. TL;DR: Be excellent to each other.

Frequently Asked Questions

Why exactly 13 kB?
Well... why not? :)
What's in it for you? Are you getting paid?
Nope, it's just my own idea and it's made for pure fun. I'd love to get a sponsorship though as I spent my own private money on the first edition to cover shipping of the prizes worldwide, making t-shirts etc.
What does the "zipped" term exactly mean?
Sent package should be zipped with your usual system archiver, the only allowed extension is .zip. Let's keep it simple - it's a competition for coders and this should be your main focus, the code itself. Thanks to the zipped archive you will easily send your game and we will easily check the file size.
Can I use Flash?
No, you can code your game using only the open web technologies like JavaScript, HTML and CSS.
Can I use WebGL?
Yes, though it might be hard to fit it into 13 kilobytes if you plan on doing an FPS game.
Can I use CoffeeScript or TypeScript?
Yes, you can use it, but you can't submit it. Only pure JavaScript code will be accepted, so remember to have your compiled code within the 13 kB limit.
Can I use compression through the self-extracting PNGs?
You can use it, but remember that the zip is as good, or even better in terms of compression than PNGs, so there's no point in doing so.
More questions?
Send them in via email or social media or post them in the dedicated topic at the HTML5GameDevs forums.


If You have any questions or propositions please feel free to contact us via e-mail:
The other options include visiting our profiles on Twitter or Facebook,
or joining our Slack channel and sending us the private message.