Enterprises often consider meeting the growing demand for an open architecture and graphic user interface for their IT systems. But this requires replacing or rewriting systems, which incurs time, expense, and risk. However, web enablement with a GUI, and extending system functionality, enable wider access to users from any device. Hence, enterprises are evaluating options to improve ways to maintain, enhance, and evolve their IBM i applications.

Front-end Modernization Techniques

Screen Re-facing

‘Read n Write’ information to 5250 data streams & host HTML/CSS webpages on the application server.

  • Quick & Easy to implement
  • Multiple IDEs available (Dev)
  • Old HTML/CSS webpages
  • Requires proprietary tools
  • Underlying monolithic system
Zend PHP Server

Runs native on AS400 by seamless integration with AS400 screen programs using Zend 5250 Bridge.

  • Uses popular web language
  • Native integration with AS400
  • Legacy system dependency
  • Installation of Zend server
RPG Open Access

Open access (handler procedure) calls the existing program to complete I/O ops using tools  (LANSA, Profound UI)

  • No load on 5250 data streams
  • Minimal AS400 modernization effort
  • Requires proprietary tools
  • Underlying monolithic system
  • Requires coding for handler program
API & UI Framework

Create new screens and leverage REST APIs to exchange information with the legacy system.

  • Lightweight services & APIs
  • Future-ready architecture
  • AS400 modules used
  • Componentized
  • Multi-vendor support
  • Dependent on AS400

What do we recommend?

To ensure a future-ready architecture and a light-weighted setup, the ‘API & UI framework’ is the most prudent technique to consider. To enable iSeries modernization using the API technique, IBMi provides multiple ways of exchanging information with core programs and databases.

Here is how it would look like to expose core business modules to external applications:

Our Approach


  • System assessment
  • Define objectives
  • Evaluate enhancements
  • Sign-off on need


  • Eligible API candidates
  • APIfication approach
  • Finalize tools
  • Project plan sign-off


  • Create APIs
  • Modernize UI
  • Complete testing
  • UAT & Go-live


  • System maintenance
  • Enhancements & fixes
  • User training
  • Documentation

Choose the right modernization partner

Just leave your details below to embark on your AS400/iSeries application modernization journey!

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