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Run Your Application Locally

You can load your application from a localhost port or a custom URL. This URL must support HTTPS to load in the web and desktop Discord clients (HTTPS is not required for mobile). When loading from localhost, your application’s network traffic does not pass through Discord’s proxy. This means any requests made by the application must use full URLs rather than mapped paths.

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Running Through a Network Tunnel

For the most accurate local development experience, we recommend testing against the Discord proxy. This ensures all URL behaviors match what you will see in production. To do this, use a network tunneling tool such as cloudflared to expose your local server. A typical pattern is for each developer to have their own development-only application. To set up a local tunnel:
1

Create a Discord application

Create a new application in the Discord Developer Portal.
2

Enable Activities

In your application’s settings, enable Activities.
3

Configure URL mapping

Set up the URL mapping for your application.
4

Start your local web server

Start your development server locally.
5

Start the tunnel

Install and run cloudflared, pointing it at your local server.
Your local web server can use HTTP. The network tunnel will upgrade the connection to HTTPS automatically.
Start the tunnel with your local server’s port (replace 3000 with your actual port): 
cloudflared tunnel --url http://localhost:3000
Once running, cloudflared will output a public URL: 
Your quick Tunnel has been created! Visit it at (it may take some time to be reachable):
https://funky-jogging-bunny.trycloudflare.com
In the Discord Developer Portal, update the URL mapping for the / prefix to funky-jogging-bunny.trycloudflare.com.
If you do not own the domain you are using to host your application (for example, ngrok’s free tier), someone else could claim that domain and host a malicious site in its place. If you use a domain you do not own, reset your URL mapping when you are done with the tunnel.

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Running in Production

The production configuration is nearly identical to local development:
1

Create an application

Create a new application in the Discord Developer Portal if you haven’t already.
2

Enable Activities

Enable Activities in your app’s settings.
3

Configure URL mapping

Set up URL Mapping with your production server’s URL at the / route.
4

Launch the Activity

Launch the Activity from the Discord client. Application URL Override should not be enabled in production.

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Launch Your Application from the Discord Client

You can see and launch all Activities owned by you or any team you are a member of via the Developer Activity Shelf. Note that an Activity will not appear on the current platform (web, iOS, Android) unless you have checked that platform in Settings > Supported Platforms in the developer portal.
  1. Go to User Settings > App Settings > Advanced and toggle on Developer Mode
  2. Enter a voice channel
  3. From the RTC Panel or Center Control Tray, click the Rocket Button to open the Activity shelf
  4. Click your Activity to launch it

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URL Mapping

Activities in Discord are sandboxed through a Discord proxy. This hides users’ IP addresses, your application’s IP addresses, and blocks requests to known malicious endpoints. As an application owner, you can configure the proxy to allow network requests to external endpoints. Because your application is sandboxed, it cannot make network requests to arbitrary external URLs. To access https://some-api.com, create a URL mapping with PREFIX set to /api and TARGET set to some-api.com. Requests from your Activity to /api will then be forwarded through the Discord proxy to some-api.com.

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How to Set a URL Mapping

Click Activities > URL Mappings in the developer portal and set the prefix and target values.

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Prefix/Target Formatting Rules

  • Do not include a protocol in the target URL. Use your-url.com, not https://your-url.com.
  • Parameter matching is supported for subdomains:
    PREFIXTARGET
    /google/{subdomain}{subdomain}.google.com
  • Targets must point to a directory, not a specific file (e.g., example.com/index.html is not supported).
  • When multiple prefixes share the same initial path, place the longer prefix first. For example, place /foo/bar before /foo, or requests to /foo/bar will never be reached.

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CSP Exceptions

The following URLs are exempt from the sandbox and can be reached without a URL mapping:
  • https://discord.com/api/
  • https://canary.discord.com/api/
  • https://ptb.discord.com/api/
  • https://cdn.discordapp.com/attachments/
  • https://cdn.discordapp.com/avatars/
  • https://cdn.discordapp.com/icons/
  • https://media.discordapp.net/attachments/
  • https://media.discordapp.net/avatars/
  • https://media.discordapp.net/icons/

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Logging

By default, the SDK forwards all console.log, warn, error, info, and debug events from your app to the Discord client.

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Viewing Logs on Desktop

Desktop logs are visible in the browser’s Developer Tools console. The Public Test Build (PTB) Discord client also supports inspecting logs via View > Developer > Toggle Developer Tools. Download PTB at discord.com/downloads.

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Viewing Logs on Mobile

1

Enable Developer Mode

In User Settings, tap Appearance and toggle on Developer Mode.
2

Open Debug Logs

Navigate to User Settings > DEV ONLY > Debug Logs.

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Filtering Application Logs

Inside Debug Logs, search for your application’s logs using:
  • RpcApplicationLogger
  • Your Application ID
Each log line is formatted as: [RpcApplicationLogger] <application-id> - message

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Sharing Logs from Mobile

With Developer Mode enabled, you can share logs from a voice channel. Swipe up from the bottom to see expanded voice controls, then tap Share Application Logs.

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Disabling Log Forwarding

To prevent logs from being forwarded to the browser: 
import {DiscordSDK} from '@discord/embedded-app-sdk';
const discordSdk = new DiscordSDK(clientId, {
  disableConsoleLogOverride: true,
});

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Forwarding Specific Log Messages

Use the captureLog command to forward specific log messages: 
import {DiscordSDK} from '@discord/embedded-app-sdk';
const discordSdk = new DiscordSDK(clientId);
await discordSdk.ready();
discordSdk.commands.captureLog({
  level: 'log',
  message: 'This is my log message!',
});