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rocketcrab is a lobby service and launcher for mobile web party games.

Join the Rocketcrab Discord!

πŸš€πŸ¦€ for developers

Add your game to rocketcrab, tl;dr:

  1. Make sure your game has mobile support, and does not require a login or registration
  2. Add an API to your game that create a new room/lobby when called
  3. Copy config/games/_template.ts and fill it out for your game
  4. ...that's pretty much it. Submit a PR!!! If you'd like more detail, keep reading!

What's a "rocket crab"???

Rocketcrab makes it easy for players to discover your game, and easily switch to and from your game without having to manually open a different website and enter a new game code. It accomplishs this by putting your game's page into an iframe, which allows any of your cookies, local storage, analytics, and advertising to continue working, while disallowing rocketcrab from manipulating your site. Integrating your game with rocketcrab should be a simple process, but please let me know by opening an issue or joining our Discord if there is any way it could be better!

The name Rocketcrab is the first thing I could think of that sounded cool, had an available .com domain, and could be represented by two emojis. It also does not have an ambigious spelling when spoken out loud (there's only one way to spell "rocket" and "crab"), which is important when trying to get your whole group to go to the site to play games!

Games are added to rocketcrab via config files located here. By looking at the config files of other games, you might be able to understand how other games implement rocketcrab, and how you might integrate rocketcrab into your game. Here's what you need to know:

Ensuring compatability

Rocketcrab works by opening your game in an iframe on all of the players' devices. At minimum, for your game to work with rocketcrab, there must be:

  • A way for rocketcrab to generate a new party via either:
    • an API that rocketcrab can hit (eg., which returns the generated game code, like abcd)
    • generating a random id that your game will accept as a valid room code
  • A way to construct a link to join a game using that game code (eg. will be opened on every player's browser, resulting in them all being in the same game together)

That's it! Many existing games already offer these, and can work with rocketcrab without any changes! But, to make the experience of playing your game with rocketcrab even better, you may need to make a few minor changes, explained in the "The automatic query params" section below.

Creating a config file

The config files, as mentioned above, should be fairly self explanatory. Along with the config template, check out the config files of other games to see how they implement rocketcrab. The most important part, which will be explained here, is the connectToGame function. This function:

  • is async, which will allow you to use await to make GET or POST requests.
  • needs to return an object with these properties:
    • player (required) an object with these properties:
      • url (required) string of the url that should be opened in every player's iframe.
        • customQueryParams (optional) a record of query params in addition to or to replace the automatic query params.
        • afterQueryParams (optional) string that will be appended to the player.url after automatic and custom query params are applied.
    • host (optional) an object with these properties:
      • url (optional) string of a url to be opened only in the "host" player's iframe. If not provided, the url from the player object will be used.
        • customQueryParams (optional) same as player object, but only applied to the host.
        • afterQueryParams (optional) same as player object, but only applied to the host.
    • These properties are explained more in depth in the config template.

Here are two examples of different connectToGame functions:

  • For Spyfall, game links are required to take the format So, instead of returning the game code from connectToGame in the code property, the game code is directly appended to the player.url before it is returned from connectToGame.
  • For Just One, we can pick our own game code! So, instead of calling to some endpoint to get a game code like Drawphone and Spyfall, the connectToGame function can itself generate a code, and we cross our fingers and hope it's unique! πŸ˜‚ The resulting player.url will look something like this:

The automatic query params

The player.url returned from connectToGame is automatically appended with 3 query params. The resulting player.url that is opened in every player's iframe will look something like this:
  • rocketcrab will always be true, well, if you're using rocketcrab, that is! πŸ˜‚ You can use this to put your game into a "rocketcrab" mode. Here are some ideas for how this could be helpful:
    • Rocketcrab itself has it's own game code system, so if your game prominentely displays its own game code, your players may be confused. If rocketcrab=true, you should hide any UI in your game that shows the game code!
    • You should also hide any "Play on πŸš€πŸ¦€" buttons (see the next section), because if rocketcrab=true, they're already playing with on rocketcrab! πŸ˜‚
  • name is a string of the name that each player has entered into rocketcrab. Use this instead of asking for your players' names a second time!
  • ishost is true for the one player that is the host of the rocketcrab party, and false for all other players. A few caveats:
    • I included this in case some one needed it, but implementing this in your game could allow any player that knows about it to make themselves host, especially outside of rocketcrab, so I don't recommend it.
    • In Drawphone, for example, the first player who joins a party is made the host. So, rocketcrab will load the host's iframe first, and will wait a few seconds before opening the iframe of the rest of the players. This is not a guaranteed solution, as the iframe API does not allow rocketcrab to know when its page has loaded.
  • There used to be an automatic code parameter for the game code. This was removed in favor of using a custom query param, detailed further in the template.

πŸš€πŸ¦€ for your existing players

If your game already has a player base, our goal is to make rocketcrab just as easy, if not easier, to use than how they already play. Rocketcrab is also a great way for your players to discover new games, which helps developers with no players yet find players for their games! So, we will want to make the process of discovering and jumping into a rocketcrab party from your game's existing lobby as painless as possible! Here's two features of rocketcrab to help:

  • Place a button on the homepage of your game that links to[your game's id here]/.
    • This will place the user in a new rocketcrab party with your game already selected!
    • Your game's ID is the id that is set for your game in its config file. For example, Drawphone's is drawphone, so the link would look like
  • Place a button in the party of your game that, when clicked by one player, will transfer all players to[your game's id here]/[insert a uuid here].
    • The first time this link is followed, it will create a new rocketcrab party. Any subsequent time it is followed, it will place users into the same rocketcrab party that was created with the same uuid.
    • Again, for the most seamless experience, when any player clicks the button, your game should automatically redirect all players in the lobby to this link right away.
    • The uuid should be unique to each lobby in your game, but the same for each player in the lobby.
    • To generate the uuid, this uuid package would be best, but any very long random string will do.
    • An example of a link for Drawphone:
    • Make sure you hide this button if the players are using you game through rocketcrab, or else they could do this!

For an example of both of these buttons in action, check out Here's what the code looked like for them.

πŸš€πŸ¦€ Behind the scenes

This is a Next.js project bootstrapped with create-next-app using the with-typescript-eslint-jest template, which includes:

Getting Started

First, run the development server:

npm run dev

Open http://localhost:3000 with your browser to see the result.

You can start editing the page by modifying pages/index.js. The page auto-updates as you edit the file.

Learn More

To learn more about Next.js, take a look at the following resources:

You can check out the Next.js GitHub repository - your feedback and contributions are welcome!