Modules

Last modified: June 16, 2025

Introduction

A Mendix app consists of modules: a System module, a UI resources package, one or more user-defined app modules, Marketplace modules, add-on modules, and solution modules. Modules are a way to split the functionality of your application into separate parts. For example, a web shop can put order management in a different module than customer and product management. Studio Pro does not enforce any kind of module structure; it is up to you to choose logical modules for your application. Some modules are part of your app by default, while others you can download in the Mendix Marketplace to add functionality to app.

The domain model is a data model that describes the information in your application domain in an abstract way.

Within a module you can define module security via module roles and specify security settings of those module roles for pages, microflows, entities and datasets.

Furthermore, a module can contain many different types of documents. Each type of document is described in its own domain-specific language (DSL). For example, user-interface forms are described by using a visual language with elements like text boxes, tables and grids. Below you see tables grouped by category of all the different kinds of documents you can create within a module.

Mendix Modules are distinct from React Native modules. Mendix modules are portions of your app which can include a data model, logic, and UI with a portable security model. React Native modules expose native Java/Objective-C and C++ objects allowing for React Native apps (in Mendix apps, you can leverage these modules via widgets or JavaScript actions to use device sensors or capabilities).

Module Types

In Studio Pro 9, add-on modules and solution modules were previously available in preview for select customers and partners as part of an early access program. In Studio Pro 10, this functionality is generally available for all users. For more information, see this page in the Studio Pro 10 Guide.

When you create a module, it has a default app module type. The type can be changed at any time in Module Settings.

There are the following type of modules:

App modules (standard modules)
Add-on modules (available starting with Studio Pro 9.12.0)
Solution modules (available starting with Studio Pro 9.12.0)

Common

Document type	Typical elements	Description
Pages	Data view, Data grid, Table, Text box	Forms are used to create a user interface for the end-user. They are composed of components that are called widgets.
Microflows	Activities, Sequence Flow	Microflows describe the logic of your application. They are composed of activities that manipulate objects, interact with the client etcetera.
Enumerations		An enumeration is a set of predefined values, for example: in a web shop, an enumeration called MemberType could have the values Gold and Silver.

Page Resources

Document type	Description
Images	Images can be used to brighten up your application. Navigation items and the various kinds of buttons have small images (icons) to left of their captions.
Layouts	Layouts specify what comes where. Each page is based on a layout. The layout contains widgets and structures that return on every page based on that layout.
Menus	A menu document defines a navigation menu that can be used by a menu widget.
Snippets	Snippets define reusable interface parts. They can be used on pages and layouts.

Resources

Document type	Description
Constants	Constants are used to define a constant value, for example: to store an URL to a webservice.
Datasets	A dataset can be used for reporting and is defined using either an OQL query or a custom Java action.
Document Templates	Document Templates are used to model a template needed as input for a document export action which can generate all kinds of documents based on application data. They are composed much in the same way as Forms.
Java Actions	With Java actions you can extend the functionality of your application in situations where it would be hard to implement this functionality in microflows. You can call a Java action from a microflow.
Regular Expressions	A regular expression is used by validation rules on an entity to describe a set of criteria that a string can match.
Rules	A rule defines a set of criteria, with a certain input the rule will result in a Boolean or enumeration depending on the criteria met. It can be called from a decision to determine the direction the microflow should go once the decision is reached.
Task Queue	A task queue runs continuously to check if any microflow tasks have been added to it and executes the tasks in the background.
Scheduled Events	A scheduled event is used to execute a microflow at a certain point in time. You can also schedule it to repeat after a given time. For example, a scheduled event can run every morning at 6 AM

Consumed Services

Document type	Description
Consumed Web Services	Importing web services of other applications (Mendix or otherwise) allows you to call those web services from your microflows.
	A domain-to-XML mapping defines a translation from domain model objects to XML objects.
	An XML-to-domain mapping defines a translation from XML objects to domain model objects.
XML Schemas	An XML schema is defined in an XML Schema Definition (XSD) file and can be imported in your model. It describes what a certain XML document should look like.

Published Services

Document type	Description
Published REST Services	A microflow can be published as a REST service operation so that it can be consumed by other Mendix applications.
Published OData Services	Persistable entities can be exposed as an OData resource, so that they can be imported by third-party applications such as Excel.
Published Web Services	A microflow can be published as a web service operation so that it can be called by third-party applications.