Set Up MEDKit User Simulation¶

Muxy.DebuggingOptions supplies local channel, user, and role context before MEDKit starts. Use it only in a local or sandbox build; a call to Muxy.debug() is not automatically removed or ignored in production.

Simulate a viewer¶

import Muxy from "@muxy/extensions-js";
const debugging = new Muxy.DebuggingOptions()
  .channelID("5678")
  .userID("1234")
  .role("viewer");

Muxy.debug(debugging);
Muxy.setup({ clientID: import.meta.env.VITE_MUXY_CLIENT_ID });

const medkit = new Muxy.SDK();
await medkit.loaded();

console.log(medkit.user.channelID, medkit.user.role);

Call Muxy.debug() before Muxy.setup(). Common sandbox roles are viewer, broadcaster, and admin. For broadcaster tests, make userID equal the channel owner's Twitch ID when the endpoint requires that identity.

Debug option reference¶

Setter	Purpose
`channelID(value)`	Simulated Twitch channel ID
`userID(value)`	Simulated current Twitch user ID
`role(value)`	Simulated role
`jwt(value)`	Use an already issued JWT instead of sandbox test auth
`environment(value)`	Override MEDKit environment selection
`url(value)`	Override the backend base URL
`onPubsubListen(callback)`	Observe local subscription setup
`onPubsubReceive(callback)`	Observe received messages
`onPubsubSend(callback)`	Observe sent messages

Treat jwt(), environment(), and url() as advanced diagnostics. Never mint a JWT in browser code or expose an extension secret to make local testing easier.

Test a Helix request¶

The sandbox authorization response does not provide a Twitch Extension Helix token. In a user-initiated click handler, call beginDebugHelixTokenFlow() to open the package's test OAuth flow:

const button = document.querySelector("#authorize-helix");
button.addEventListener("click", async () => {
  await medkit.loaded();
  medkit.beginDebugHelixTokenFlow();
});

Complete the flow in the opened window, then reload the test page. The 2.4.18 package restores the testing token from local storage and exposes it as medkit.user.helixToken.

Clear the local testing token when finished:

window.ClearHelixToken?.();

Continue with Call the Twitch API from an Extension. Twitch documents the token's endpoint restrictions in its Extension front-end API guide.