---
title: raise_lua_event
summary: An MD action that sends a named event to Lua UI.
section: reference
kind: api
status: reference
tags: ["X4","modding","raise","lua","event"]
sources: ["https://wiki.egosoft.com/X4%20Foundations%20Wiki/Modding%20Support/"]
---
## Return value

| Type | Meaning |
| --- | --- |
| [none (MD action)](wiki:type-md-values) | No Lua return. The param expression supplies a value to the receiving Lua handler. |

[Types and methods](wiki:types)

## Observed form


Layer: Mission Director, inside `actions`. `name` is an MD expression returning the event name; `param` is a payload expression. Inner quotes form MD string literals. Register the Lua receiver beforehand with [RegisterEvent](wiki:register-event).




```xml
<raise_lua_event name="'Wiki.Pong'" param="'pong'" />
```



**What happens:** Lua receives a Wiki.Pong event with the payload "pong". A visible message requires an explicit action by the Lua handler.

## Returning a result


The project uses strings for small results and an agreed begin/chunk/end series for larger ones. Receiving one chunk does not establish snapshot completeness.



## Limits


An event delivers UI data; it does not automatically persist an operation journal. Define the persistence boundary for both effect and outcome. Encode user values before putting them into a delimiter-separated wire format. The simple pong example intentionally avoids complex user text.