BizTalk is an integration engine with a toolbox of adapters. It can speak to files, databases and web APIs as well as enterprise systems like SAP and message queues. Messages enter, pass through pipelines and maps (think XSLT) for validation and transformation, and orchestration lets you model processes that span hours or days. A rules engine allows business logic to live outside code, and tracking/monitoring helps you see what happens at every step.

What makes BizTalk special is its breadth and maturity: a large adapter library, built-in support for EDI/AS2 and industry accelerators for finance and healthcare, plus trading partner management. Development happens in Visual Studio with schemas, maps, pipelines and orchestrations; deployments are typically handled via MSI and bindings, enabling versioned and reproducible environments.

Today BizTalk often exists in hybrid architectures. Many organizations keep stable on-prem flows where latency, transactions and legacy systems demand it, while complementing them with cloud services for new integration needs. A common approach is to let BizTalk remain the engine behind the scenes while modern interfaces and event-driven components land in the cloud - getting the best of both worlds without ripping out proven systems.