---
title: container - X4 schema type
summary: container: X4 attribute schema type: base types, constraints and value alternatives.
section: reference
kind: guide
status: reference
updated: 2026-10-27
tags: ["XSD","schema","types"]
sources: ["https://wiki.egosoft.com/X4%20Foundations%20Wiki/Modding%20Support/","https://www.w3.org/TR/xmlschema11-2/"]
---
## Meaning

container: X4 attribute schema type: base types, constraints and value alternatives.

An XSD type constrains XML, rather than declaring a Lua return or the payload type of event.param. A valid schema value does not prove a successful game effect.

## Schema structure

`libraries/common.xsd`

| Property | Value |
| --- | --- |
| Construction | `restriction` |
| Base type | [`expression`](wiki:schema-expression-b8bc0e4f) |

restriction narrows a base type; union accepts one of its branches; list describes whitespace-separated items. Enumeration values in one restriction are alternatives. Pattern syntax is XML Schema regex, not Lua patterns or JavaScript RegExp. Constraints inherited from the base type still apply.

## Example and result

Use the attribute pages below for contextual examples. A generic executable example is not inferred from a type name alone.

## Used by

| Element | Attribute | Schema |
| --- | --- | --- |
| [`event_object_docked`](wiki:api-mdevent-event-object-docked-76ee1269) | `dock` | `libraries/common.xsd` |
| [`event_object_undocking_started`](wiki:api-mdevent-event-object-undocking-started-887ea3ea) | `dock` | `libraries/common.xsd` |
| [`find_buy_offer`](wiki:api-md-find-buy-offer-2b617170) | `tradepartner` | `libraries/common.xsd` |
| [`find_buy_offer`](wiki:api-md-find-buy-offer-2b617170) | `buyer` | `libraries/common.xsd` |
| [`find_buy_offer`](wiki:api-md-find-buy-offer-2b617170) | `seller` | `libraries/common.xsd` |
| [`find_sell_offer`](wiki:api-md-find-sell-offer-720d9012) | `tradepartner` | `libraries/common.xsd` |
| [`find_sell_offer`](wiki:api-md-find-sell-offer-720d9012) | `buyer` | `libraries/common.xsd` |
| [`find_sell_offer`](wiki:api-md-find-sell-offer-720d9012) | `seller` | `libraries/common.xsd` |
| [`remove_docking_request`](wiki:api-md-remove-docking-request-bfb5b4ff) | `container` | `libraries/common.xsd` |
| [`request_docking`](wiki:api-md-request-docking-ac1b3c21) | `container` | `libraries/common.xsd` |


[All schema types](wiki:schema-types) · [Lua / MD value types](wiki:types)