Methods and Technologies of IT System Integration

The integration method you choose today defines the speed, resilience, and cost-efficiency of your business tomorrow. This article helps you navigate the trade-offs.

Following on from Part 2, which examined the strategic patterns of system integration, this article shows how these concepts can be implemented in practice using proven technologies and methods. The aim is to ensure that integration decisions are technically sound and future-proof.

1. File-based integration

In file-based integration, system A generates a file (e.g., CSV, JSON, XML) and stores it in a designated location (local storage, FTP server, or cloud bucket). System B periodically checks for new files, retrieves them, and processes the data. Scheduled jobs (e.g., cron jobs, Windows Task Scheduler) are typically used to automate this exchange.

Associated patterns:

• Batch Data Integration
• Pull Integration
• Point-to-Point Integration

Advantages: Simple and cost-effective to implement. No need for real-time connectivity between systems.

Disadvantages: No real-time synchronization, manual error handling, risk of version conflicts and data inconsistencies, requires additional validation and processing before data import.

When to use: For periodic data transfers where real-time processing is not critical (e.g., nightly batch imports).

Common Technologies: SFTP, AWS S3, Windows Task Scheduler, CSV, XML, JSON file formats.

2. Database-level integration

Database-level integration involves two systems accessing a shared database or synchronized databases. Data exchange occurs through SQL queries, database replication, stored procedures, or triggers. Alternatively, systems may use database views or ETL processes to read and write data independently.

Associated patterns:

• Synchronous Integration (for direct database reads/writes)
• Batch Data Integration (in replication scenarios)
• Tightly Coupled Integration

Advantages: Direct access, high performance, ability to leverage native database capabilities like triggers and replication.

Disadvantages: Strong dependency on database schema and structure, scalability and performance issues in large deployments, increased risk of breaking data integrity and transaction consistency, difficult to manage schema changes across dependent systems.

When to use: When systems need fast access to shared data and are built around the same database environment.

Common Technologies: SQL (PostgreSQL, MySQL, Oracle Database), NoSQL (MongoDB replication, Cassandra), data replication tools (e.g., Oracle GoldenGate, AWS Database Migration Service).

3. API-based integration

API-based integration connects systems via standardized APIs (typically RESTful or SOAP APIs). System A sends an HTTP request (GET, POST, PUT, DELETE) to System B’s API, which processes the request and returns a response, often in JSON or XML format. Authentication and authorization are enforced through methods like OAuth 2.0 or JWT.

Associated Patterns:

• Synchronous or Asynchronous Integration
• Real-Time Integration
• Loosely Coupled Integration
• Push Integration

Advantages: Real-time communication, high flexibility, cloud-friendly, strong control over access, security, and service versioning.

Disadvantages: Requires careful API lifecycle management and documentation, API outages or breaking changes can disrupt dependent systems, security vulnerabilities if APIs are not properly protected.

When to use: For integrating dynamic applications, cloud services, mobile apps, and microservices architectures.

Common Technologies: REST APIs, GraphQL APIs, gRPC, OAuth 2.0, OpenID Connect, JWT, Tools like Postman, Apigee API Management, AWS API Gateway.

4. Enterprise Service Bus (ESB)

An Enterprise Service Bus acts as a centralized communication backbone between multiple systems. Each system connects to the ESB, which handles routing, transformation, orchestration, and monitoring of data flows between participants. Advanced ESBs can also apply business rules or conditional routing based on data content or context.

Associated Patterns:

• Centralized Integration
• Loosely Coupled Integration
• Asynchronous Integration (often with support for messaging systems)

Advantages: Simplifies integration architecture by centralizing management, supports complex orchestration, data transformation, and error handling, high scalability for large enterprise environments.

Disadvantages: Higher cost and complexity compared to direct integrations, if not properly designed, the ESB can become a bottleneck or single point of failure, requires robust governance and monitoring to avoid “monolithic ESB syndrome.”

When to use: In large organizations integrating dozens or hundreds of heterogeneous systems.

Common Technologies: MuleSoft Anypoint Platform, WSO2 Enterprise Integrator, Red Hat Fuse, IBM App Connect.

5. Event-driven integration

In event-driven integration, systems communicate by producing and consuming events rather than making direct calls. System A publishes an event (e.g., “order created”) to an event broker, and subscribing systems react asynchronously. This approach decouples senders and receivers, improving scalability and resilience.

Associated Patterns:

• Asynchronous Integration
• Real-Time Integration
• Loosely Coupled Integration
• Push Integration

Advantages: Near real-time processing with low latency, highly scalable and resilient against system failures, reduces system coupling, promoting flexibility and adaptability.

Disadvantages: More complex event modeling and data flow management, requires robust event brokers and monitoring mechanisms, increased difficulty in tracing and debugging event chains across distributed systems.

When to use: In IoT systems, e-commerce platforms, financial transactions, and real-time analytics environments.

Common Technologies: Apache Kafka, RabbitMQ, AWS EventBridge, Azure Event Grid.

6. iPaaS – Integration Platform as a Service

iPaaS solutions provide cloud-based platforms for building and managing integrations between cloud and on-premise systems through pre-built connectors and low-code development environments. Users can orchestrate workflows visually, map data transformations, and automate processes without heavy custom coding.

Associated Patterns:

• Centralized Integration
• Loosely Coupled Integration
• Real-Time and Batch Data Integration
• Push and Pull Integration

Advantages: Fast time-to-market with prebuilt connectors and templates, supports multi-cloud and hybrid integration scenarios, reduces the need for deep technical expertise in early integration stages.

Disadvantages: Subscription costs may increase significantly with scale, may have limited flexibility for highly customized or performance-critical integrations, risk of vendor lock-in if proprietary components are heavily used.

When to use: When organizations need rapid, scalable, and flexible integration capabilities without building everything from scratch.

Common Technologies: SAP Cloud Platform Integration (SAP CPI), Informatica Cloud Application Integration (CAI), Dell Boomi, Workato, MuleSoft Composer, Microsoft Power Automate.

7. Hybrid Integration Architectures

A single integration approach rarely prevails in practice. Successful companies combine different methods depending on the application.

An overarching, event-driven approach often forms the backbone of the architecture. API calls, file exchange, or database access are used in a targeted manner within individual domains.

Example:

When an order is placed:

1. The Order domain publishes an OrderPlaced event on the Event Bus.
2. The Email domain listens for that event and triggers logic to build a confirmation email for the customer.
3. The Email domain uses an API-based integration to retrieve email content from the CMS system.

This approach illustrates how event-driven architecture acts as a backbone, while point-to-point API communication is used tactically where direct interaction is appropriate.

Hybrid integration allows organizations to stay modular, avoid unnecessary coupling, and leverage the strengths of multiple methods — provided the integration strategy is governed consistently.

Conclusion: From vision to implementation

Technical implementation plays a decisive role in determining the future viability of an integration strategy. Those who consciously deploy technologies in line with strategic patterns create robust and scalable IT ecosystems. Hybrid architectures provide the necessary flexibility to optimally support departments, business models, and innovation cycles.

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