What Is Middleware? Definition, Guide & Examples

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Working in between the operating system and the applications running on it, middleware can offer protocols and capabilities to applications beyond what the operating system provides. 

Middleware is a type of software that can support connectivity or communication between multiple application components or applications not designed to connect to each other within a distributed network. Middleware is also a tool that can streamline application development. 

There are several types of middleware that can provide various functions, such as messaging, security authentication, web application servers, database management, and API management. Within an enterprise, middleware can help to connect all the necessary components serving as a centralized integration hub in a cloud-based system. 

Middleware has a range of applications to help provide services for and connections between applications that they do not traditionally have.

What is middleware?

Middleware was initially a type of go-between working between the application front end, or the user, and the back-end resource like the database or mainframe application. Today, it has evolved into all forms of connectivity between two or more applications, including both front-end and back-end connectivity, and connecting resources within the cloud. 

Middleware is software that enables applications to communicate and connect to each other in ways that they were not designed to — so, outside of their native capabilities. Middleware can form the translation layer between an operating system and the applications running on it. 

Middleware is often called the “software glue,” as it facilitates communication between multiple applications while acting as the intermediary.

Types of middleware

There are a variety of different types of middleware and provided services. The types of middleware you will use will depend on what services you require. For example, middleware can be used for authentication purposes or to set up SSO (single sign-on). It can also be used for messaging, distributed processes, or transaction management. 

Some different types of middleware include the following:

  • Database middleware: This eases and streamlines the interaction with and access to back-end databases. It is commonly some form of a SQL database server.  
  • API middleware: This allows other developers to connect to your applications by providing tools to create, manage, and expose APIs for your applications. This can include API management platforms, API developer portals, and API gateways.  
  • Message-oriented middleware (MOM): This transforms or translates messages between applications that are using different messaging protocols to enable communication as well as manages the routing of the messages. This can include message brokers and message queues.  
  • Object request broker (ORB) middleware: This works with CORBA (Common Object Request Broker Architecture) as a broker between requests and fulfillment of requests among different applications or components within the same distributed system.  
  • Remote procedure call (RPC) middleware: This allows applications, even those on remote systems, to trigger a procedure in another application to enable them to seem as if they are all part of the same application.  
  • Portal middleware: This enables a seamless front-end integration as well as smooth interactions between the client device and back-end systems. It integrates capabilities and content from multiple related applications to form a single composite application.  
  • Device middleware: This is used to develop applications to run in a certain hardware environment, such as a specific mobile OS.  
  • Asynchronous data streaming middleware: This enables data sharing between various applications by replicating a data stream in an intermediate store and allowing for real-time data streaming.  
  • Transactional middleware: This supports the implementation of data transactions across a distributed network often using TPMs (transaction processing monitors) to keep transactions moving through the steps from data exchange to completion. 

Middleware & cloud computing

Cloud computing can add a layer of complexity for developers. With cloud computing, applications are commonly deployed across multiple infrastructures with varying architectures from on-premises systems to public clouds. This can involve multiple frameworks, tools, and languages. Middleware can simplify this by helping to manage the complexity in a simpler manner.

With middleware, developers can work seamlessly across a highly distributed platform. Middleware can help to make app development smoother, faster, and more cost-effective by providing services that allow the different components of a distributed system to work together and communicate effectively. 

Middleware can create a centralized “hub” where all of the various applications, services, and components can be integrated within for easier access and management. With middleware, you can develop your application in one location and deploy it anywhere.

What does middleware have to do with app development?

Middleware can enhance app development by providing a method to connect application services, microservices, computing resources, devices, and/or data sources without requiring the developer to create custom integrations each time. Middleware can then streamline this development process and help the developer get the application to market sooner. 

Business applications need to run at scale, on-site, and across cloud environments. Therefore, they need to be built within an integrated application environment with the ability to carry out necessary actions. 

Different applications need to be able to communicate using common messaging frameworks, which can include REST, SOAP, XML, or JSON. Middleware can provide services to help with this as well as the ability to enable communication between components written in multiple computer languages like C++, Java, Python, and PHP.

Middleware also includes services that enable developers to configure and control integrations and connections, which can customize the response from the back-end application based on the front-end application’s request. Enterprise middleware can also help to scale to distribute client requests across the entire environment to dynamically manage traffic across distributed systems. 

Middleware uses network security protocols, such as TLS (transport layer security) to establish secure connections and transfer data. Middleware can also provide authentication capabilities.

Layers of middleware for app development

For application development purposes, there are four layers of middleware, which include the following:

  • Container layer: Managing the delivery of application lifestyles in a consistent manner, this layer includes container management, service mesh, and DevOps capabilities.  
  • Runtimes layer: Containing the execution environments for custom code, this layer provides a runtime hosting environment. For highly distributed cloud environments, this middleware can offer lightweight frameworks and runtimes as well as speed up data transfers with messaging and data access through in-memory caching.  
  • Integration layer: Connecting assets such as purchased and custom apps and SaaS (software as a service), this layer forms functioning systems using APIs, messaging, and integration. This layer of middleware also provides API management, data and event streaming, in-memory data cache, and database services.  
  • Process management and decision management layer: Adding decision management, critical intelligence, automation, and optimization, this layer of middleware is the last layer of development middleware.

Application development tooling is an additional feature of middleware that helps with code sharing and joint development by offering preset containers and templates to build applications. This can facilitate a consistent and cohesive experience for both application development and delivery on-premises and in the cloud.

Middleware applications

The different types of middleware can provide services to aid in web application development, making this process easier and faster. Middleware can help applications to better communicate and integrate components and resources within a distributed system in a centralized fashion. 

Middleware has a variety of applications based on the services you require, which can include the following:

  • Link legacy systems with new technologies
  • Messaging services
  • Data storage
  • Security authentication
  • API management
  • Build and run applications at scale within multi-cloud and containerized environments
  • Database access and interaction
  • Real-time data streaming

Middleware can expand the scope of your operating system by enabling different components and applications within your distributed system to manage data and communicate effectively.

Additional resources

One of the most commonly used and popular open-source middleware tools for real-time data streaming is Apache Kafka. This is a type of asynchronous data streaming middleware. 

Business strategies can be enhanced using integration platform as a service (iPaaS) in a cloud-hosted model, connecting services, apps, data, and processes across on-premises, private, and public cloud environments. There are a variety of options and middleware software products to help with functions your operating system is not designed to do natively.


CORBA. (2022). Object Management Group, Inc.

Apache Kafka. (2017). Apache Software Foundation.

How Modern Integration Platform-as-a-Service (iPaaS) Enables Business Strategy. (December 2021). International Data Corporation (IDC).