Middleware is software and cloud services that provide common services and capabilities to applications and help developers and operators build and deploy applications more efficiently. Middleware acts like the connective tissue between applications, data, and users.
Middleware has been part of software engineering terminology since the late 1960s, and as a category can apply to a wide range of modern software components. Middleware can include application runtimes, enterprise application integration and various kinds of cloud services. Data management, application services, messaging, authentication, and application programming interface (API) management are all commonly handled by middleware.
Today middleware is the technological foundation for modern cloud-native architectures. For organizations with multi-cloud and containerized environments, middleware can make it cost-effective to develop and run applications at scale.
As a broad category, middleware can encompass everything from web servers to authentication systems to messaging tools. Here are a few of the common use cases for middleware in modern development.
New application development
Middleware can support modern and popular runtimes for a variety of use cases. Developers and architects can work with agility across platforms, following sets of foundational runtimes, frameworks, and programming languages. Middleware can also deliver commonly used functions such as web servers, single sign-on (SSO), messaging, and in-memory caching.
Optimization of existing applications
Middleware can help developers transform legacy monolithic applications into cloud-native applications, keeping valuable tools active with better performance and more portability.
Middleware integration tools connect critical internal and external systems. Integration capabilities like transformation, connectivity, composability, and enterprise messaging, combined with SSO authentication, make it easier for developers to extend capabilities across different applications.
Application Programming Interfaces (APIs)
Many middleware services are accessed through APIs, which are sets of tools, definitions, and protocols that allow applications to communicate with each other. APIs make it possible to connect completely different products and services through a common layer.
While APIs are one way to share data between applications, another approach is asynchronous data streaming. This replicates a data set in an intermediate store, where the data can be shared among multiple applications. One popular open source middleware tool for real-time data streaming is Apache Kafka.
Intelligent business automation
Middleware can help developers, architects, IT, and business leaders automate manual decisions. Automation can improve resource management and overall efficiency.
As organizations move more toward cloud-native development, software developers and systems architects have had to focus on the up-front design and architecture of their application platforms. This requires selecting and setting up frameworks and capabilities for developing, deploying and running applications—all functions handled by middleware. With these capabilities in place, an organization can get more benefits of the cloud. Applications can be deployed across multiple infrastructures, from on-premises systems to public clouds, and still work as intended.
Organizations turn to middleware—much of which is now offered as cloud services, simplifying deployment and management—as a way to manage complexity and to keep application development quick and cost-effective. Middleware can support application environments that work smoothly and consistently across a highly distributed platform. It can also support software supply chain security, DevSecOps strategies, and automation, helping teams build new and better apps faster while still managing security risks.
Modern business apps are engineered to run at scale, on premises, and across clouds. To build them, developers need an application environment with unified foundational capabilities. Middleware is the key to assembling such an environment.
We can think of these capabilities in 4 layers, plus tooling:
The container layer
The runtimes layer
This layer contains the execution environments for custom code. Middleware can provide lightweight runtimes and frameworks for highly distributed cloud environments such as microservices, in-memory caching for fast data access, and messaging for quick data transfer.
The integration layer
Integration middleware provides services to connect custom and purchased apps, as well as Software-as-a-Service (SaaS) assets through messaging, integration, and APIs to form functioning systems. It can also deliver in-memory database and data cache services, data/event streaming, and API management.
The process automation and decision management layer
This final layer of development middleware adds critical intelligence, optimization and automation, and decision management.
In addition to these 4 layers of middleware there’s application development tooling. This allows teams to build applications using preset templates and containers, and facilitates efficient code sharing and joint development. Tooling supports a consistent and coherent application development and delivery experience on-premises and cloud.
APIs establish a set of definitions and protocols for integrating software, letting one application communicate with other products and services. APIs simplify how developers integrate new application components into an existing architecture, thereby helping teams collaborate and making it faster to add useful new functions to software.
The use of APIs and microservices are a foundational part of cloud-native application development. The services that facilitate API connectivity are a kind of middleware. API management tools give developers the ability to share, distribute, control, and monetize APIs.
Along with other application services tools, such as service mesh and data streaming, API management can make it possible to run applications at scale across a hybrid cloud environment.