JSON Message Communication

This page explains how to exchange JSON messages between your frontend and Unreal Engine application on Streampixel.

📘Overview

Streampixel uses a messaging channel between your frontend and the Unreal Engine app to exchange JSON.

• Messages from Unreal → Frontend: status updates, events, analytics.

• Messages from Frontend → Unreal: configuration, commands, live input.

There are two distinct methods for sending messages from the frontend to Unreal:

1. Startup Parameters (URL)

   • A one-time JSON passed in the URL when launching the app.

   • Delivered automatically at session start.

   • Requires no frontend code.

2. Runtime Messages (WebSDK / Iframe API)

   • Interactive messages sent anytime after the app is running.

   • Requires using Streampixel’s WebSDK or Iframe integration.

   • Ideal for dynamic, user-driven experiences.

Both methods deliver messages into Unreal through the same Pixel Streaming system. From Unreal’s perspective, there is no difference in handling; you can branch logic based on the content of the JSON.

Unreal Side – Sending & Receiving JSONFrontend Side - Sending & Receiving JSON