Criteria for choosing integration architecture for IT systems
As the number of microservices grows, companies face a choice between the simplicity of point-to-point connections and implementing an integration layer (ESB or API Gateway). Direct integration is only effective for a small number of stable connections. When the number of systems (N) grows, the number of connections increases according to the formula N*(N-1)/2, creating tight coupling and risking cascade failures across the entire network.
What this means for the market
For businesses, maintaining direct connections beyond 5+ integrations leads to opaque management and high operational risks. Without a single contract management layer, development teams spend up to 27.7% of their working time fixing integrations rather than delivering new features, which directly impacts time-to-market and increases infrastructure overhead.
When architecture needs to change
Experts highlight several indicators of a critical threshold:
- Number of nodes: managing direct connections becomes opaque once you exceed 5+ integrations.
- API contract changes: without a single contract management layer, teams can spend up to 27.7% of their working time fixing integrations.
- Transaction requirements: guaranteed message delivery requires brokers, not just synchronous HTTP requests.
Functional distribution of tools
The modern approach involves a clear separation of concerns between technologies:
- API Gateway: centralizes authentication, rate limiting, and traffic monitoring.
- Event Streaming (e.g., Apache Kafka): used for high-load asynchronous processes where throughput and event replayability are critical.
- ESB (Enterprise Service Bus): used in complex enterprise environments for data format transformation (e.g., SOAP to JSON) and integration with legacy systems.
To avoid infrastructure overhead, companies use modern platform solutions. For instance, the domestic platform UnityBase allows for the gradual deployment of managed integration layers thanks to automatic REST API generation and a built-in security subsystem.
Next steps
If the existing point-to-point architecture is unstable, an evolutionary transition is recommended. Follow these practical steps:
- Address critical connections first: Deploy a lightweight API Gateway to manage the most critical integrations.
- Migrate transactional processes: Move to asynchronous message broker channels to eliminate tight coupling of microservices.
- Leverage platform solutions: Use modern platforms like UnityBase for gradual deployment of managed integration layers with automatic REST API generation.
Prepared by a Software Ukraine member. Original publication.