Enterprise Application Integration (EAI): Comprehensive Guide for Business Management

Enterprise Application Integration (EAI) Apps

Enterprise Application Integration (the abbreviation EAI is often used) represents an approach to process-oriented integration of enterprise applications that makes it possible to manage the complexity of heterogeneous application systems, avoid data redundancy, and optimize business processes in order to achieve increased flexibility on the one hand and cost savings on the other. Ultimately, enterprise application integration helps to fully exploit hidden synergy potentials of existing systems.

In this blog post it will be explained which advantages EAI offers, which integration approaches exist and in which way enterprise applications can be integrated.

The most important advantages

Because integration is associated with high risks and effort, companies are still hesitant when it comes to integration projects. On the other hand, there are benefits that can justify the necessary effort and look quite convincing. What companies get from enterprise application integration:

360-degree view of business processes

Enterprise Application Integration enables participants to gain a comprehensive view of various aspects along the value chain – be it customer management, supply chain management, asset management and others.

By integrating data from multiple customer touchpoints (which are touchpoints between the company and customers along the entire customer journey such as customer portals, websites, social media channels, physical stores/shops/offices, or even employees), your company can get a comprehensive picture of customer interactions and offer tailored loyalty programs.

Integrating order management software with customer service software provides an opportunity to get an overview of all customer orders with status information, thereby improving customer service and support. In supply chain management, unified access to consolidated information from various sources such as accounting and inventory management software and a supplier portal is enabled, which significantly contributes to the development of a long-term strategy.

Optimized business processes

Enterprise Application Integration not only integrates different IT landscapes, but also links related business processes. Regardless of whether standard or custom software, new or legacy systems, external or internal data sources are involved, it is possible to map all business processes, make them more transparent, standardize them as needed, and optimize them as a result. For example, by connecting inventory and supplier management software, a company can more accurately replenish inventory or manage sales more efficiently to meet increasing demand with supply.

Ease of use

Since constantly switching between application systems is not only inconvenient but also time-consuming, enterprise application integration enables you to avoid duplication of efforts and related errors. For example, connecting CRM and DMS solutions can simplify the lives of sales teams, increase efficiency, and improve sales and marketing activities. Since a CRM system is the main tool responsible for processing and managing customer or prospect data, integration makes it possible to get quick access to relevant information (terms, scope of services, cooperation models).

More opportunities to deploy modern technologies

Enterprise application integration makes it possible to introduce modern technologies such as IoT, data analytics and AI-based tools into business processes. By aggregating cross-enterprise data and ensuring its consistency, there are more diverse opportunities for training machine learning algorithms.

What are the levels of integration?

Depending on how deep the level of enterprise application integration should be in your project and what your requirements are, we talk about four types of integration: data integration, functional integration, presentation integration and business process integration. To determine what your organization needs, we suggest answering the next questions:

  • Do you want unified access to consistent data from multiple applications? Data integration enables the sharing of data that is merged from different data sources, stored centrally in a data store, and presented in a uniform format to avoid redundancy and ensure data consistency across the enterprise. At the same time, diverse applications function independently of each other. Data from other apps can be reused as needed.
  • Do you want functions that are used to accomplish certain common tasks and are available in different systems to be available only through a third-party application? It’s all about function integration, providing access to the business logic of other applications or legacy software. This means that a function call to one application causes corresponding calls in other applications, allowing relevant operations to be performed. This helps eliminate duplicate functions, simplify updates, and reduce new app development costs.
  • Want to create a new business process while reusing the logic of existing apps? That’s where business process integration comes to the rescue. When creating a new distributed business process, the existing code of your applications can be used in a new way. A separate integration management component (also called a choreographer) can coordinate the work of a modeled workflow. Coordination occurs thanks to the linking of different programs responsible for individual steps along a business process. For example, retailers can provide their customers with advanced information about shipping conditions and order status by integrating supplier inventory management software, shipping service provider portals, or their own warehouse management software. This type of integration helps tremendously to increase the value of previous investments and reduce the cost of app development and maintenance.
  • Want to get access to multiple apps through a unified user interface to avoid switching between different screens? This is possible through display integration. This type of integration is the easiest and fastest way to organize the communication between different applications through the presentation logic and present these applications using a unified interface, which greatly contributes to work optimization and error reduction.

The chosen integration layer will serve as the basis in deciding which architecture, integration methods and approaches will be used in building your future integration solution.

Integration Methods and Approaches in EAI: Overview of Advantages and Limitations

We do not aim to cover all existing methods. But we would like to go into more detail about three of the most popular approaches to creating integration solutions to date: a legacy shared database, a much-discussed service-oriented architecture (SOA), and an increasingly popular robotic process automation (RPA).

Shared database

The oldest option is to integrate multiple applications by introducing a shared database. In this scenario, a number of applications use the same data from a shared database, which is also brought into a uniform data format. Project costs vary from €1 million to more than €9 million for medium and large enterprises, depending on the size and complexity of the solution.


  • Exceptional data consistency – All data changes are immediately available.
  • Relatively fast response time – There are no additional abstraction layers (interfaces) used to transfer data.


  • Single point of failure – Failure of the shared database results in the failure (partial or complete) of all connected applications.
  • Complicated database changes – To make the required changes, all applications connected by the shared database must be harmonized.
  • Increased security risks – External solutions have direct access to the stored data.
  • No integration with ready-made products – Each platform-based solution such as SAP, ERP or Salesforce CRM has its own databases and cannot be integrated in this way.

Service-oriented architecture (SOA)

The promising SOA-based approach makes it possible to build a customizable architecture in which all processes and applications are linked by means of independent, agile and reusable Web services. This type of architecture is oriented around business processes and supports distributed data processing, which also explains why service-oriented architecture is used in enterprise application integration. Because all applications are integrated into this type of architecture, it enables companies to respond to changes in running processes in near real time and increase agility.

Although this approach is gaining traction, each company must decide which business processes and applications need to be broken down into reusable components. It is important to note that the service-oriented architecture enables both simpler changes to existing services and rapid introduction of new services.

If your organization chooses SOA-based integration, there are two common implementation methods to choose from: Point-to-Point Connection and Enterprise Service Bus (ESB).

Point-to-point connection

This connection variant allows services to communicate directly with each other.


  • These connections can be created relatively quickly and easily – This is suitable for the case when only a few services need to be coordinated.
  • Lower startup costs – The cost of point-to-point connections starts from 3,000 euros when only minimal customization is required.


  • Increasing complexity – The increasing number of connections required when integrating new systems leads to the increasing number of interfaces and increasing complexity. From this, a recommendation can be made to design the linkage in the form of a hub when there is a large number of applications (which is the case in enterprises today).
  • Increased effort for changes as well as integration of new services – Since services are closely linked, the interfaces of all already integrated components with which a new component to be integrated will communicate must be adapted. This takes a lot of time, resulting in longer changes and increased susceptibility to failure.
  • Complex and costly maintenance – As the number of integrated services and interfaces required to connect them increases, so does the amount of maintenance required. As a result, it is difficult to design and maintain complex systems and landscapes with 20, 100 or more integrated services using point-to-point integration.

Enterprise Service Bus (ESB)

An enterprise service bus, as a central component of the service-oriented architecture, represents an intermediary that assumes all responsibility for communication between services and applications, enables the integration of distributed services, and takes care of message processing and forwarding according to predefined rules, process orchestration, and security management. Special adapters allow applications to communicate with the Enterprise Service Bus to transform messages from one format to another.

The cost of ESB implementation varies widely. If a free open-source ESB solution is used, companies must factor in support costs in this case (these vary depending on whether support activities are performed internally or handled by an external support provider). Another option is to use commercial ESB solutions. The licensing cost of purchasing a standard ESB solution (including support services) can range from €25,000 to €180,000 per year, depending on the vendor. The most popular commercial ESB products include Microsoft BizTalk, Oracle ESB, IBM WebSphere ESB and Mule ESB.


  • Resilience to overload – Because messages are independent of the specific receiver, load balancing is enabled and failover is provided.
  • Enhanced security – Typically, such mechanisms as authentication and authorization, encryption and tokenization are built into the ESB solution to protect services from unauthorized access.
  • Faster updates and scaling – You do not need to rewrite all APIs. Only the adapter from the changed service needs to be updated.
  • Legacy software integration – The legacy solution is not able to communicate with modern protocols like REST or SOAP. In this type of integration, no changes are required to the legacy applications because an ESB acts as an interpreter to ensure smooth communication.


  • Single point of failure – Similar to a shared database, ESB failure can cripple the entire enterprise IT structure.
  • Lower performance – Due to an increased number of intermediate components (adapters, routers, choreographer, etc.).
  • Middleware licensing costs – These can amount to higher amounts for complex systems.

Potential risks with EAI

When it comes to Enterprise Application Integration, there are also some risks that need to be considered from the very beginning. Before your company makes a decision, we would like to draw your attention to three potential risks and their possible causes:

  • Data quality can suffer during integration.

The reasons for this can be very diverse: Incompatibility of data stored in different formats; transfer of erroneous data from one system to others; integration of duplicate data; during the journey between different layers or applications, data can be lost, deleted or corrupted, etc. If your company relies on poor quality data, it will lead to wrong decisions and actions.

To avoid this, we recommend checking data quality (as well as the quality of sources) according to recognized data quality criteria even before integration using reliable tools and procedures; taking necessary measures to clean data; using appropriate mechanisms for data validation and transformation; storing the resulting data in a structured way and in specified formats; correcting erroneous or incomplete data.

  • Integration can create security risks.

Integration into a system makes information easier to find. But this is where a danger arises: security-related problems occur due to direct and often uncontrollable access to resources. Moreover, integration often implies remote communication over the network, which also poses serious privacy and security risks.

To avoid this risk, we recommend being careful when assigning access rights and controlling and monitoring access; using proven authentication and authorization protocols; creating security policies; and considering additional mechanisms for encryption.

  • Mistakes can happen to anyone – integration is no exception.

To ensure smooth enterprise application integration, software testing is essential. When integrating applications, errors have a wide range of “opportunities” to sneak in: Creation of new connections, decoupling of processes and structures, interaction of diverse building blocks, lack of synchronization, different descriptions of interfaces, inheritance of errors from legacy systems, and more.

To overcome these challenges, engage a professional testing team with experience in integration projects to perform required tests, with good knowledge of integration methodologies and middleware for enterprise applications, and a deep understanding of different integration layers and architectures.