HTML5 and JavaScript Game Development Competition in just 13 kB

What is js13kGames?

js13kGames is a JavaScript coding competition for Web Game Developers running yearly since 2012. The fun part of the compo is the file size limit set to 13 kilobytes. The competition will start at 13:00 CEST, 13th August and end at 13:00 CEST, 13th September 2024. Theme will be announced on August 13th.

Read GitHub's tips and tricks article, check the Resources for tools, read the Blog,
buy swag at the Shop, and subscribe to the Newsletter - good luck and have fun!

Interested in some history? Check out the editions from previous years:
2023, 2022, 2021, 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2013, 2012.

The competition is organized by Andrzej Mazur from Enclave Games.

2024 competition starts in:

Latest blog post: Every gadget all at once

Platinum Partners

To be announced.

Gold Partners

GitHub Poki Arcadia

Silver Partners

OP Games

Bronze Partners

Enclave Games Gamedev.js

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


Richard Davey

Richard Davey

Richard is the founder and CTO of Phaser Studio Inc, the team behind the Phaser game framework and Phaser Editor. An avid gamer since the 1980s, he loves seeing how creative devs can become when forced into limitations such as 13KB.

@photonstorm |

Clément Pasteau

Clément Pasteau

CTO at GDevelop, creating the tools that will lower the entry to game creation and make it accessible to anyone. Passionate about improving the place and the image of video games in our world.

@ClementPasteau |

Joep van Duinen

Joep van Duinen

Joep leads the game developer operations team at Poki, the global market lead on web. Poki is on a mission to create the ultimate online playground: a place where players and game developers come together to play and create. Together with a growing 300+ game developer community, they're creating the new standard for web games. Interested in getting your creation out to millions of players or reading up on the latest web tech?

@joepvduinen |

Paul Gadi

Paul Gadi

Paul is CTO ⁄ Co-Founder of OP Games, focused on helping game developers successfully create decentralized games. He also leads the KERNEL Gaming Guild, a fellowship of the most talented builders in Web 3. He loves exploring the intersection of new technologies with game design, and believes that decentralization and shared virtual economies will revolutionize how we play games.

@polats |

Victor Debone

Victor Debone

Victor is a software engineer passionate about design and the user experience. He thinks games are the ultimate user experience. Given that, they require feedback and early exposure, which is the best gift judges can provide to JS13kGames participants and what he's here to do!




To be announced.



To be announced.


JS13K floppy disk

10 × js13kGames 2014 floppy disk

js13k 2024 swag: ten original floppy disks with all js13kGames 2014 entries.

JS13K medal

13 × js13kGames medal

js13k 2024 swag: thirteen medals originally given to the 2023 winners.

js13kGames VR cardboard

20 × js13kGames VR cardboard

js13k 2024 swag: twenty original VR cardboards from 2017.


40 × js13kGames 2018 CD

js13k 2024 swag: forty original CDs with all js13kGames 2018 entries.

JS13K keychain

70 × js13kGames keychain

js13k 2024 swag: seventy original keychains from 2021.

JS13K magnet

100 × js13kGames magnet and bottle opener

js13k 2024 swag: one hundred original magnets and bottle openers from 2019.

JS13K pen

100 × js13kGames pen

js13k 2024 swag: one hundred original metal pens from 2020.

JS13K coaster

100 × js13kGames coaster

js13k 2024 swag: one hundred original coasters from 2022.

JS13K pin

100 × js13kGames metal pin

js13k 2024 swag: one hundred original metal pins from 2023.

JS13K patch

100 × js13kGames patch

js13k 2024 swag: one hundred original material patches from 2023.

JS13K hologram sticker

100 × js13kGames hologram sticker

js13k 2024 swag: one hundred new hologram stickers.


5 × Phaser subscription

Five Phaser subscriptions: two Professional licenses and three Developer licenses for 12 months each.

GitHub Copilot

13 x GitHub Copilot

Thirteen GitHub Copilot licenses for individuals for 12 months each.

Vampire Survivors

10 × Vampire Survivors bundle

Ten copies of Vampire Survivors bundle: a game by Poncle along with all four DLCs each available on Steam.


9 × WebStorm license

Nine personal licenses for WebStorm JavaScript IDE created by JetBrains.


13 × CSSBattle Plus account

Thirteen CSSBattle Plus accounts for 6 months each.

Web Maker

13 × Web Maker Pro account

Thirteen Web Maker Pro accounts for 6 months each.


10 × PlayCanvas account

Ten PlayCanvas Personal plans for 12 months each.

Construct 3

2 × Construct 3 license

Two Personal licenses of Construct 3 game engine for 12 months each.

GDevelop Pro

7 × GDevelop Pro license

Seven GDevelop Pro licenses - a no-code, easy game-making app.


5 × Aseprite license

Five Aseprite animated sprite editor and pixel art tool licenses by David Capello.



To be announced.



To be announced.


There are four different categories, you can submit your game to any of them - it's up to you.

Desktop category


Full power of the hardware.

Mobile category


Handheld touch devices.

There's a blog post about the Unfinished one which is a special category
for submitting incomplete, bugged, or oversized entries so they won't be judged.

Outgoing links

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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 in the top level folder structure (not a subfolder) 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 permitted (although you are allowed to ask users to live-load a web font to support some characters or emoji on devices that can't display them properly, but you have to make sure your game will work without them). Analytics and other stat-collecting scripts are also not allowed. All the game assets should fit in the package size limit (the A-Frame, Babylon.js, and Three.js frameworks are not counted towards the size limit, but you can use them only in the WebXR category). 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

Main theme for the competition is announced on August 13th. 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 2024

The competition starts at 13:00 CEST, 13th August 2024 and ends at 13:00 CEST, 13th September 2024. No submissions will be accepted after the end of the competition, although there may be exceptions to that.


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. On the other hand, you have the right to report any game publisher that will link to (or iframe) your entry on their portal without your permission.

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. Also, submitting Breakout or Flappy Bird clones taken out of a tutorial make no sense at all - try creating something at least a little bit more original. You can, however, use any available libraries and resources that are not yours, but you have the right to use them.

Errors and browser support

Your game must work and be playable in at least two browsers: latest Firefox and Chrome, but the more supported browsers, the better. There should be no errors - you can lose some points if your game is showing any errors in the console. Don't stress too much if there are any warnings, but if we cannot play your game, then 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, giving feedback, and announcing winners

The voting among the participants will last for three weeks between September 15th and October 4th, winners will be announced on October 5th. Experts will give the games constructive feedback (one per game) during the same three week period - their comments will also be published on October 5th.

Save data ⁄ persistent memory

Remember to add prefix to your variables and create a namespace for your game when you save data to localStorage as all the games on the server share the same memory when played in the browser. Also, be sure to NOT use localStorage.clear() as it will wipe out all the data of all the other games. Manipulate the data you are sure is yours.

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. For more details see Berlin Code of Conduct.

Privacy policy

By entering your email address and sending a game through the submit form you agree to receive email communication about important events of the competition like announcing the winners or sending out the digital prizes, but also curated content from the partners about their tools, services, or job offers. I will never share your email with anyone though.

By submitting, you also grant the competition organizers the right to re-use the uploaded materials for advertisement of the competition in any form.

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 making t-shirts, shipping of the prizes worldwide, 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 gam... oh, nevermind.
Can I use CoffeeScript or TypeScript?
Yes, you can use it, but you can't submit it. Only JavaScript code will be accepted, so remember to have your compiled code within the 13 kB limit. This is to ensure that the submitted entries are an actual HTML page with scripts, not a binary.
Can I use WebAssembly and ⁄ or Rust?
Yes, after all those are web technologies, and can work well with JavaScript games if used properly.
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.
Do I have to register somewhere?
No, you just need to submit your game through a form when it's ready.
How many games can I submit?
As many as you want, there are no limitations.
More questions?
Send them in via email or social media.


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 end3r a private message.