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ESB vs Middleware: What’s the difference?

Thanks to an ESB, applications can move work uniformly and can subscribe to messages based on simple business and structural policy rules. In this article we will explain the differences between Middleware and ESB technologies:

What does Enterprise Service Bus (ESB) mean?

An Enterprise Service Bus (ESB) is a design pattern that mediates between the client and the service. It is capable of changing the format and the protocol of data communication to achieve that the two ends of the conversation can reach an understanding by means of the compatibility created.

We can also define an ESB as a software tool that has the purpose of mediating between different applications in order to establish communication between them, taking into account a series of criteria that have been established beforehand. These applications do not communicate with each other directly but take advantage of the ease the ESB provides for them to work together.

What is Middleware?

Middleware is a software layer that acts as an intermediary between different applications, systems or software components. Its main purpose is to facilitate communication and integration between these elements, abstracting the complexities of networks and communication protocols. Middleware provides common services and functions, such as distributed communication, data access, transaction management and security. Its focus is on interoperability and connectivity between systems, allowing applications to interact without requiring significant changes to their internal logic.

Differences between ESB vs Middleware technologies

When it comes to establishing the differences between ESB andMiddleware, it should be made clear that an ESB is one of the tools in the middleware ‘Integration’ subcategory. An ESB contributes to the integration of numerous applications by playing an intermediary role of routing, filtering, mediating and transforming messages.

When we talk about middleware technologies, we are referring to a more generic and general concept, which encompasses everything from integration tools to content and document management, including web portals, business process management and application servers. It establishes effective and agile communication between the databases and the applications used by the user at the end of the process, or a Commercial Off-The-Shelf application (COTS), whether it is an Enterprise Resource Planning (ERP) or a Customer Relationship Management (CRM).

It is safe to say that an ESB is one of the integral parts of today’s middleware tools, but it is not the only tool that should be considered under this denomination. Nevertheless, it is highly valued for its primary function, which is to facilitate that services and systems are brought to a common standard to be integrated as needed at any given time by the users of an organisation.

Features that define and differentiate an ESB

The following is a summary highlighting the main differences between an ESB (Enterprise Service Bus) and Middleware:

  • Focus: Middleware focuses on facilitating communication and overall integration between heterogeneous applications and systems. On the other hand, the ESB focuses specifically on orchestration and management of enterprise services.
  • Functionalities: Middleware provides common services and functions such as distributed communication and data access. The ESB, in addition to these basic functionalities, offers advanced capabilities such as routing, complex data transformation and service monitoring.
  • Architecture: Middleware can take different forms and technologies, such as application servers, messaging systems and communication protocols. In contrast, the ESB is based on a specific service bus architecture, which enables the connection and orchestration of business services.
  • Routing: The best ESBs make it easy to change routing on the spot, while the routing rules can also be modified so that business processes adapt to the specific needs of the moment. Moreover, an ESB will present a method for generating or accessing metadata that documents the request/response interfaces and the interfaces of the enterprise components that exchange information. The XML format is the format commonly used to present ESB metadata, with interface definitions in WSDL. As far as web services are concerned, an ESB will support basic web services standards for communication. This includes SOAP, XML and WSDL.
  • Connections: With an ESB it is possible to make connections between enterprise components that developers have generated, even if they have done so on stand-alone equipment. This function must be added to the already described function of integrating applications.

-Maybe you are interested: Are the microservices the end of the ESB?

Compared to other forms of middleware architecture, an ESB is characterised because it supports both request and response communication as well as one-way communication. This means that the best ESBs have very high error tolerance and scalability, as well as advanced data storage and forwarding capabilities.


An ESB is particularly suitable when advanced message management is required, such as complex data transformations, routing rules and flow control. On the other hand, a Middleware is more appropriate when the main objective is to facilitate communication and interaction between systems, without going into specific messaging details.

The final choice between an ESB and Middleware will ultimately depend on the specific integration requirements and needs of each project or company. It is important to carefully evaluate the features and functionality of each option before making a decision.

Still not sure what type of technology you need for your company? Contact us and we will guide you through the selection process so you can make the best decision for your company.

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