For the past 3 decades, AS400 has evolved in a big way. IBM has tried to keep the latest generation of the IBM i servers open, more powerful, and far more technologically advanced than what these servers once used to be. While technology leadership of organizations using the IBM iSeries might be eager for a change, they need to realize the true potential of the machine & bring about a transformation that is technologically & economically prudent.

Different Front-end Modernization Technique

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, IBM 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 application modernization journey!

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