BizTalk Server 2013 comes in the following four editions:
Enterprise edition: This has been designed for customers with enterprise-level requirements for high volume, reliability, and availability. It allows an unlimited number of applications and supports failover for multiple Message Boxes.
Standard edition: This has been designed for customers with moderate volume and deployment scale requirements. It allows five applications and uses a single Message Box. Both the Enterprise and Standard editions support complete EAI, B2B, and Business Process Management functionalities. They include industry accelerators for RosettaNet, HIPAA, HL7, and SWIFT.
Branch edition: This has been designed for customers with hub and spoke deployment scenarios, including RFID. It allows only one application.
Developer edition: This traditionally has all of the functionalities of the Enterprise edition, but it has been licensed for development and testing only.