# Enterprise Integration Patterns

> The architecture of connecting systems: integration styles, API gateways, message queues, event-driven architecture, and service mesh — ESB vs modern, a decision framework, and the governance that stops integration becoming a distributed monolith.

*Source: https://www.lazlosoftwaresolution.com/guides/enterprise-integration-patterns*

**Enterprise integration patterns** are reusable solutions for connecting independent systems so they exchange data reliably and at scale — spanning integration styles (point-to-point, hub-and-spoke, API-led, event-driven) and building blocks (API gateways, message queues, event streaming, service mesh). The goal is to replace brittle point-to-point connections with a governed, loosely coupled architecture.

Integration is where enterprise complexity actually lives: a modern estate runs hundreds of systems, and point-to-point wiring degrades into an N² web where one change breaks three things. The modern posture is a **federated capability under central governance** — an API plane (gateway fronting managed, versioned APIs) for north-south traffic and an event backbone for loose coupling, with a service mesh managing east-west traffic once you have many services. Design for idempotency, contracts, and versioning; catalog everything; authenticate and least-privilege every connection.

API security concentrates at the gateway — a specialisation of [enterprise application security](/guides/enterprise-application-security) — and the connector layer normalises SaaS like [Salesforce](/technologies/salesforce) and [HubSpot](/technologies/hubspot) into your model. Delivered via [Enterprise Integration](/services/enterprise-integration); start with [designing an API your customers will not hate](/blog/designing-an-api-your-customers-will-not-hate).