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 2017. Theme for 2017 was: lost.
Read Tuts+ Gamedev intro article, check the Resources page for useful tools,
and see the Rules for details - good luck and have fun!

The competition is organized by Andrzej Mazur from Enclave Games,
be sure to check out the new A-Frame category this year.


Mozilla Codility GitHub
Intive Blur Spartez Casumo


AirConsole Jscrambler LoadView

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


Tomasz Wesołowski

Tomasz Wesolowski

Engineering Lead at Codility. During the day, responsible for frontend and integrations; after work a passionate gamer who never really grew out of the 90's titles.

@KosGD |

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 |

Pablo Farías Navarro

Pablo Farías Navarro

Game developer and founder of Zenva. Since 2012, Pablo has been teaching online how to create games, apps and websites to over 200,000 students through Zenva Academy, and created content for companies such as Amazon and Intel.

@ZenvaTweets |

Jimmy Joe McGurl

Jimmy Joe McGurl

Director of Gaming at BLUR, Ranked professional gamer (59th in North America) and top commentator for Super Smash Bros., CRT-loving Retro Gamer.

@ohjimmyjoe |

Mitri Wiberg

Mitri Wiberg

Veteran developer and producer. An Anime and Manga buff. The Afro Samurai in the growing Casumo gaming team. He’s got the style, the moves, the hair – OK maybe not the hair. Join him and the Casumo team on their mission to create innovative games and generally kick ass!

@CasumoCasino |

Victor Debone

Victor Debone

Rodent's Revenge veteran player, web developer at Spartez, 2015's js13k participant (my little secret how I ended at Spartez actually...) and a JavaScript fanatic.

@victordebone |

Winners - Desktop


1st place Greeble by Ryan 'Rybar' Malm


2nd place LOSSST by Maxime Euziere


15th place Mauja by Viktor & Pavlo


18th place EYESORE! by Alastair Pearce

    31-40. At Journey's End, Pandemia, The Lost Dungeon, Ælbahkat: The Lost Islands, Where We're Going, We Do Need Roads, they will find you, City of Lost Drones, They Are Lost, GL-Escape, Lost in Asterion
    41-50. Riding Hoods, Formation Absent, A King's Journey: Chapter 3: Trapped & Poisoned, Lost in the woods, Square, Divine Descent, Escape, Lost In Labyrinth, The Forest, 13K bytes under the seas
    51-60. The Wrong Universe, Lost in Confusion, Explorer camp, Lost, Lost Love, Greedy Circles: The maze of riches, Fear the Dark, Lost Luggage, Lost Pixels, Lost Luna
    61-70. Veda's Run, muri, Verloren, Lost Worlds, Deep Inside, DEEP SPACE, The forgotten cave, Epic Loot, Ghost Goes Lost, Spacefield League
    71-80. Concentration Lost, Save the Lost Friend, Hoosdere, Down the Drain, Round Royale, Lost Compass, All is not lost., Run Chicken Run, Alien Millionaire, Lost Fleet
    81-90. Lost Time, 3D Lost Maze, Me Myself and i, Get Gerry Home, Mazeren, Lost in Deep Space, Incurable, Lost Square Adventures, Raider of the Lost Gems, Twisted Tunnels
    91-100. Lost Caves, I’ve lost my parents!, LostintheWoods, Vendredi, A Tourist in Paris, Lost Soul, Lost in the Stars, Lost in Vim, Adrift to the Abyss, Lonely soul

Winners - A-Frame

    16-20. Metamorphosis, A-Snake, where?what?, Don't let your dreams be memes, Fly South

Winners - Mobile


1st place LOSSST by Maxime Euziere


8th place Mauja by Viktor & Pavlo

    21-30. Round Royale, Run Chicken Run, Alien Millionaire, Lost Time, Get Gerry Home,
    Raider of the Lost Gems, Just Plane Astray, A Tourist in Paris, Adrift to the Abyss, Lonely soul

Winners - Server

Community Awards winners

Voted among the developers themselves.

  • 1. Mauja by Viktor & Pavlo - 41 points
  • 2. LOSSST by Maxime Euziere - 38 points
  • 3. Lost Beacons by Rémi Vansteelandt - 28 points
  • 4. Greeble by Ryan 'Rybar' Malm - 26 points
  • 4. Where is Winston by Gheja_ - 26 points
  • 6. Where We're Going, We Do Need Roads by Mark Vasilkov - 16 points
  • 6. EYESORE! by Alastair Pearce - 16 points
  • 8. A moment lost in time. by - 14 points
  • 8. Coconutty by Mary Knize - 14 points
  • 10. BUNNY LOST! by Eoinmcg - 13 points
  • 11. Adrift by Dhmstark - 12 points
  • 12. Lost Marbles by Rene Hangstrup Møller - 11 points
  • 12. You Are Lost by Rebecca - 11 points
  • 14. Just go straight by Pierre Gimond - 10 points
  • 14. Lost in Asterion by Santiago Zapata ⁄ Slashie - 10 points
  • 14. Pandemia by Satanas - 10 points
  • 17. Fear the Dark by Renae & Dave - 9 points
  • 18. Riding Hoods by Keltzow - 8 points
  • 19. AMAZ3D by Greweb - 7 points
  • 19. At Journey's End by Corson, Todd, Kevin - 7 points
  • 19. City of Lost Drones by Igor Khotin - 7 points
  • 19. Lost on Stranger Terra by Csaba Csecskedi - 7 points
  • 23. Rogue Scavenger13K by LuisQuin - 6 points
  • 23. Lost Treasure by SamirH - 6 points
  • 23. Instructions lost by ElGregos - 6 points
  • 23. Cat Meow by Lislis - 6 points
  • 27. Search of Sounds by Vitalii Liapin - 5 points
  • 27. Alien Millionaire by Piotr & Igor - 5 points
  • 29. Lost in Vim by PiGames - 4 points
  • 29. DEEP SPACE by Kieran Smith - 4 points
  • 31-37. A Tourist in Paris, Splat Paddlers, Vernissage, Veda's Run,
    Ælbahkat: The Lost Islands, Divine Descent, Lost Bricks - 3
  • 38-52. Lost in CYBERSPACE, Lonely Soul, Trapped in the Hyperdimensional Maze, The Lost Dungeon,
    PrisonRi0t, Pacman lost in tiles, Metamorphosis, Lost in my mind, DACHU, Escape, Epic Loot,
    Formation Absent, Get Lost Hombre!, Have you missed the TUTORIAL for life? - 2
  • 53-72. Lazer Car, Incurable, Lost Soul, World Lost, The Wrong Universe, The Game, The Walls Are Lasers, Lost Sessions With Bob,
    Me Myself and I, Lost in Jungle, Lost in Confusion, Lost in Font, Galactic Winds II: The Lost Battle, Lost Luna, Lost in squares,
    Fly South, Get Gerry Home, Buoing: Black Hole, Castaway, A King's Journey: Chapter 3: Trapped & Poisoned - 1

Social Special winners

For the most popular games on the social networks.

Twitter Special

Facebook Special

Google+ Special


Evil Glitch

3 × Evil Glitch game

Three copies of Evil Glitch game by Agar3s available on Steam.


30 × GitHub account

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


10 × PlayCanvas account

Ten 6-month PlayCanvas Personal accounts offering a cloud-hosted, collaborative platform for building games.

Construct 3

2 × Construct 3 license

Two Personal licenses for one year each of Construct 3 game engine created by Scirra.

1 × account

One account with Startup plan for 12 months.


7 × WebStorm license

Seven personal licenses for WebStorm JavaScript IDE created by JetBrains.


3 × Jscrambler license

Three Jscrambler Professional licenses for three months each.

AirConsole Hero

∞ × AirConsole Hero

Unlimited subscription plans of the AirConsole Hero for one year each for every participant of the competition.


3 × CodePen Pro account

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


2 × $13 Amazon voucher

Two Amazon gift vouchers worth $13 each, sponsored by the Phaser framework created by Rich Davey, admin of the HTML5 Game Devs forums.


5 × NodeBB hosting

Five Hamlet hosting plans for 12 months each from the NodeBB team.

Cloud9 IDE

5 × Cloud9 IDE subscription

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


10 × JSBin Pro account

Ten JSBin Pro accounts for 6 months each from Remy Sharp.


2 × Dotcom-Monitor

Two Dotcom-Monitor performance monitoring accounts.


There will be four different categories, you can submit your game to any of them - it's up to you.
There's a special page for everything about the new A-Frame category if you want to know more.

Desktop category


Full power of the hardware.

Mobile category


Mobile touch devices.

Server category


Node.js multiplayer.

A-Frame category


WebVR experience.

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 13 games

  • 1st place:, CodePen Pro, Kendo UI, JSBin Pro, Phaser Editor
  • 2nd-3rd places: CodePen Pro, Kendo UI, JSBin Pro, Phaser Editor
  • 4th-5th places: Kendo UI, JSBin Pro, Phaser Editor
  • 6th-10th places: JSBin Pro, Phaser Editor
  • 11th-13th places: Phaser Editor

Mobile category

Top 10 games

  • 1st-2nd places: Construct 3, WebStorm, ImpactJS, Kenney Game Assets 2
  • 3rd-4th places: WebStorm, ImpactJS, Kenney Game Assets 2
  • 5th place: ImpactJS, Kenney Game Assets 2
  • 6th-10th places: Kenney Game Assets 2

Server category

Top 5 games

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

A-Frame category

Top 10 games

  • 1st-3rd places: WebStorm, VR Gamedev mini-degree, PlayCanvas
  • 4th-5th places: VR Gamedev mini-degree, PlayCanvas
  • 6th-10th places: PlayCanvas

Social Specials

Twitter Specials (for the highest number of tweets)

  • 1st place: Phaser Amazon, Cloud9 IDE
  • 2nd-5th places: Cloud9 IDE

Facebook Specials (for the highest number of likes)

  • 1st place: Phaser Amazon, Making Money with HTML5
  • 2nd-5th places: Making Money with HTML5

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

  • 1st place: Kenney Asset Forge, Zenva Gamedev course
  • 2nd-5th places: Zenva Gamedev course

Community Awards

Top 30 entries (voted among developers themselves)

  • 1st place: Kenney Asset Forge, Evil Glitch, Glitchbuster, GitHub
  • 2nd-3rd places: Evil Glitch, Glitchbuster, GitHub
  • 4th-10th places: Glitchbuster, GitHub
  • 11th-30th places: GitHub

Prizes for every entry

All submitted games

  • js13kGames 2017 t-shirt, A-Frame cardboard, stickers, AirConsole Hero subsciption


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 2017 is: lost. 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 2017

The competition starts at 13:00 CEST, 13th August 2017 and ends at 13:00 CEST, 13th September 2017. 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.