RPG Modernization for a Leading Oil Refinery

Our Client

A prominent US based oil refining company operating complex financial, billing, and order processing systems on AS/400.

Business Need

The client depended on a suite of outdated AS/400 applications for billing, payables, receivables, and reporting. Most of the system was developed in RPG II, and there were parts that went back several decades. It had gradually become more difficult to maintain, challenging to modernize, and riskier to operate.

Key challenges included:

• Complex RPG programs with undocumented logic, built over many years.
• Heavy dependence on Profound UI with limited modernization success.
• Shortage of skilled AS/400 developers and middleware expertise
• Aging code and brittle integrations that created operational risk.
• Need for modern web interfaces without disrupting core processes.

The business required a carefully controlled, low-risk modernization strategy that would maintain stability while enabling long, term transformation.

Solution

Damco conducted an enterprise-level AS/400 ecosystem assessment and implemented a phased RPG modernization strategy aligned with business priorities.

Modernization Approach

• Proof of Concept Validation Demonstrated UI modernization using React and Node.js middleware before full-scale rollout.
• Phased RPG Refactoring Refactored RPG II programs in stages, enabling dual-run systems to maintain operational continuity.
• Modern UI Enablement Replaced green-screen workflows with modern web interfaces for finance and operations teams.
• Database Modernization Modernized inquiry and prompt screens using SQL/ODBC with DB2 for improved maintainability.
• Hybrid Delivery Model Deployed a blended onshore-offshore team, following Agile practices for predictable delivery.
• Knowledge Preservation Built a centralized knowledge repository to document legacy logic and reduce dependency on niche skills.

Business Impact

The client was able to update vital systems while keeping complete control over ongoing operations, thanks to the phased approach:

• Enhanced usability in the billing, accounts payable, and receivable workflows
• Improved access to the transportation and sales analysis modules
• Profound was no longer required for UI modernization.
• Faster onboarding and reduced training time with intuitive web interfaces
• Stable modernization without disruption to core financial processes

Key Metrics

• 40% reduction in accounts payable turnaround time
• 35% improvement in order processing accuracy
• $1.5M+ projected cost savings through AI-assisted development

Engagement Snapshot

• Applications/Modules: 13+
• Programs: 2,500+
• Codebase: 3M+ lines of code
• Engagement Since: 2024

Where Things Stand Now

The refinery currently operates with modern web, based interfaces alongside the refactored RPG backends that are running in parallel with the legacy systems. Finance and operations teams are able to perform their tasks more quickly with improved visibility and accuracy, whereas the dependency on niche AS/400 skills has been reduced. This way, the refinery can continue to modernize in different phases without the risk of a shutdown of their core operations.