Microsoft BizTalk Server

Microsoft BizTalk Server is an inter-organizational middleware system (IOMS) that automates business processes through the use of "adapters" which are tailored to communicate with different software systems used in an enterprise. Created by Microsoft, it provides enterprise application integration, business process automation, business-to-business communication, message broker and business activity monitoring.
BizTalk Server was previously positioned as both an application server and an . Microsoft changed this strategy when they released the AppFabric server which became their official application server. Research firm Gartner consider Microsoft's offering one of their 'Leaders' for Application Integration Suites. The latest release of Biztalk (Biztalk Server 2020) was released on 15th of January 2020. 
In a common scenario, BizTalk integrates and manages automated business processes by exchanging business documents such as purchase orders and invoices between disparate applications, within or across organizational boundaries.
Development for BizTalk Server is done through Microsoft Visual Studio. A developer can create transformation maps transforming one message type to another. For example, an XML file can be transformed to SAP IDocs. Messages inside BizTalk are implemented through the XML documents and defined with the XML schemas in XSD standard. Maps are implemented with the XSLT standard. Orchestrations are implemented with the WS-BPEL compatible process language xLANG. Schemas, maps, pipelines and orchestrations are created visually using graphical tools within Microsoft Visual Studio. The additional functionality can be delivered by .NET assemblies that can be called from existing modules—including, for instance, orchestrations, maps, pipelines, business rules.
Brief history of Microsoft BizTalk Server.
Starting in 2000, the following versions were released:
Features.
The following is an incomplete list of the technical features in the BizTalk Server:
Human-centric processes cannot be implemented directly with BizTalk Server and need additional applications like Microsoft SharePoint server.
Architecture.
The BizTalk Server runtime is built on a publish/subscribe architecture, sometimes called "content-based publish/subscribe". Messages are published into BizTalk, transformed to the desired format, and then routed to one or more subscribers.
BizTalk makes processing safe by serialization (called "dehydration" in Biztalk's terminology) - placing messages into a database while waiting for external events, thus preventing data loss. This architecture binds BizTalk with Microsoft SQL Server. Processing flow can be tracked by administrators using an Administration Console.
BizTalk supports the transaction flow through the whole line from one customer to another. BizTalk orchestrations also implement long-running transactions.
Adapters.
BizTalk uses adapters for communications with different protocols, message formats, and specific software products. Some of the adapters are: electronic data interchange, file, HTTP, SFTP, FTP SMTP, POP3, SOAP, SQL, MSMQ, MLLP, Azure Logic App, Azure API Management, Microsoft SharePoint Server, IBM mainframe zSeries (CICS and IMS) and midrange iSeries (AS/400) server, IBM DB2, IBM WebSphere MQ adapters.
The WCF Adapter set was added with 2006 R2. It includes: WCF-WSHttp, WCF-BasicHttp, WCF-NetTcp, WCF-NetMsmq, WCF-NetNamedPipe, WCF-Custom, WCF-CustomIsolated adapters. Microsoft also ships a BizTalk Adapter Pack that includes WCF-based adapters for LOB systems. Currently, this includes adapters for SAP and Oracle database, Oracle E-Business Suite, Microsoft SQL Server, MySQL, PeopleSoft Enterprise and Siebel Systems.
Additional adapters (for Active Directory, for example) are available from third party Microsoft BizTalk core partners.