The HostBridge JavaScript Engine


HB.js is a complete solution for rapidly developing and deploying reusable CICS APIs.

For organizations that have a continuing investment in CICS® applications, the HostBridge JavaScript Engine (HB.js) enables creation of JavaScript/JSON-based integration scripts and APIs. HB.js scripts work with all types of CICS applications without relying on screen scraping.

With HB.js, you can:

  • Modernize CICS applications by creating a services boundary to them
  • Orchestrate CICS terminal-oriented transaction micro flows as single services
  • Orchestrate and aggregate transactions, programs (e.g., COMMAREA), and data into single composite services
  • Integrate any mainframe with any distributed app – Web and mobile applications, cloud architectures, service-oriented architectures (SOAs), other enterprise applications, etc.
  • Create dynamic object-oriented applications that simplify and revitalize legacy applications for modern environments. HB.js fully supports a wide range of object-oriented scripting/Web services types and protocols, including JavaScript, JSON, XML, SOAP, SOAP 1.2, RESTful services, Ajax, Atom, HTML, and E4X (ECMAScript for XML).


With HB.js, developers can easily incorporate complex CICS transaction micro flows that can involve interaction with dozens or even hundreds of screens into a single, reusable Web service.

Integrating these micro flows using sub-optimal, middle-tier integration technologies has serious performance implications: they require a full request-response cycle with the mainframe for each transaction, driving up latency.

Instead, HB.js executes the entire transaction sequence on the mainframe, orchestrating and aggregating all relevant data and returning a single response, typically with sub-second response times. This approach is more reliable, more efficient, lowering response times and costs.

Hybrid and Composite Apps

HB.js allows an existing portfolio of CICS applications to easily participate in hybrid IT strategies. Customers can integrate valuable, legacy applications with hybrid applications, or modernize complex legacy applications as new, composite apps. Whatever the end goal – integration, modernization-in-place, or replatforming – HB.js supports all these objectives through the object-oriented capabilities of HB.js. Developers can simply write new, dynamic applications within a Web services application architecture.

Production Environment

HB.js is zIIP-enabled, runs inside CICS, and supports:

  • CICS 3270 screen-based transactions
  • BMS, non-BMS, 3270, and CA application types
  • COMMAREA programs
  • DB2®, VSAM™, DL/I, Datacom®, and other data assets
  • Connectivity via HTTP, LINK/EXCI, Enhanced WebSphere MQ
  • Extended Multi-Region Operation (MRO)
  • Other CICS and z/OS tools and technologies.

Development Environment

Developers can use HB.js to expose z Systems apps and data using the same high-performance, industry-standard technologies used by today’s leaders in mobile, web, and cloud computing. The HostBridge Eclipse Integrated Development Environment (IDE) allows developers to easily and rapidly author, test, and deploy HB.js scripts/Web services and complies with DevOps standards and best practices. The IDE includes HB Transaction Explorer, a graphical display that precisely replicates CICS screens. Using this tool, developers can navigate live terminal-oriented CICS application micro flows to develop highly reliable integration scripts/services.

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