> ## Documentation Index
> Fetch the complete documentation index at: https://docs.streampixel.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> How to send and receive JSON between your page and Unreal — three paths, each with its own API.

How you talk to Unreal depends on **how you embed the stream**. All three paths can send AND receive — they just use different APIs.

| Path                             | Send to UE                                           | Receive from UE                                                                                                                                           |
| -------------------------------- | ---------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Default frontend (share URL)** | URL query params: `?key=value` (one-time, at launch) | Built-in handlers — opens URLs, takes screenshots, shows keyboard, toggles cursor (see [Default frontend](/resources/quick-start-guide/default-frontend)) |
| **Iframe `postMessage`**         | `iframe.contentWindow.postMessage(...)`              | `window.addEventListener('message', ...)`                                                                                                                 |
| **Web SDK**                      | `emitUIInteraction(...)`, `emitConsoleCommand(...)`  | `addResponseEventListener(...)`                                                                                                                           |

Pick **one** based on how you embed. Don't mix the APIs across paths — even though everything ends up in the same UE message system, the frontend-side calls are different.

## Important — UE-side setup is the same

The Blueprint setup on the Unreal side is **identical** regardless of which frontend path you use. Set it up once and it works for URL params, iframe `postMessage`, and the Web SDK.

## Where to read next

|                                                                                                              |                                                                                           |
| ------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------- |
| [Unreal side](/resources/json-message-communication/unreal-side-sending-and-receiving-json)                  | Blueprints to receive frontend messages and send your own. Shared across all three paths. |
| [Default frontend](/resources/quick-start-guide/default-frontend)                                            | What the share link handles automatically, plus URL-param syntax.                         |
| [Frontend side (URL params)](/resources/json-message-communication/frontend-side-sending-and-receiving-json) | Detailed URL syntax for one-time messages at launch.                                      |
| [Iframe communication](/resources/iframe-integration/frontend-and-application-communication)                 | Send and receive via `postMessage`.                                                       |
| [Web SDK communication](/resources/web-sdk/features/communicating-with-ue)                                   | The SDK's programmatic methods and event listeners.                                       |