Discord's new Embedded App SDK - How Colyseus fits in?

Create immersive, instant multiplayer experiences without downloads within the Discord App

Discord & The Embedded App SDK

Discord has long been the go-to platform for communication and community building among game developers & players. It provides the social layer where people hang out before, during, and after games.

Now, with the introduction of the Embedded App SDK, Discord has the potential to become a viable publishing platform for your HTML5 multiplayer games. This SDK enables developers to seamlessly integrate their experiences directly within the Discord app via an iframe.

Matt Hova and Colin Loretz

Watch in full Introducing the Embedded App SDK presentation with Matt Hova and Colin Loretz

Example: React Colyseus

The “React Colyseus Example” project made by the Discord team showcases how Colyseus can be used to power multiplayer games within a Discord Activity.

In this demo, the Embedded App SDK is used to detect whether the user starts or stops talking, and the game state is updated accordingly.

In short, in this demo, Colyseus make it seamless to:

  • Group players together in a game room, based on the channelId they are in.
  • Synchronize the game state between all players in real-time

Example: Webgame Template

The Colyseus Webgame Template has been updated to support the Embedded App SDK.

When launched via a Discord Activity, this demo will sign-in the user with Discord to identify its username and be able to store their score in the leaderboard.

Users that join directly from the website are matched together in the same game room.

React Colyseus Demonstration Project

Colyseus Webgame Template project

iframes, Content Security Policies and URL Mappings

One of the key highlights of the Discord Activities is its sandboxed environment - your app resides within a designated “discordsays.com” URL and is loaded via an iframe.

If your game requires access to external URLs or services, configuring “URL Mappings” via the app’s developer portal is a must:

Discord Developer Portal: URL Mappings

Discord Developer Portal → “Your App Name” → Activities → URL Mappings

Discord will act as a proxy for all requests made from your app, ensuring that the Content Security Policy (CSP) is enforced and that your app is secure.

The Embedded App SDK is currently in developer preview and has a few limitations. Soon Discord is going to introduce Discovery and Monetization options as well.

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