IBM i has earned its reputation as a dependable platform for mission-critical business applications. Across manufacturing, distribution, retail, logistics, and other industries, organizations continue to rely on IBM i for order processing, inventory management, financial transactions, and essential business operations.

But while the core applications may remain reliable, the integrations surrounding them can become increasingly difficult to maintain.

Over time, organizations accumulate custom interfaces, scheduled file transfers, manual workarounds, and application-specific connections. Each solution may have addressed an immediate business need, but together they can create a complicated integration environment.

This is known as IBM i integration technical debt.

Technical debt does not necessarily mean an application is outdated or poorly designed. It means previous technology decisions have created ongoing maintenance costs, limitations, or risks that make future changes more difficult.

The good news? Addressing IBM i integration technical debt does not require replacing your existing RPG applications.

By identifying integration bottlenecks and introducing reusable APIs, organizations can simplify connectivity while preserving trusted business logic.

Here are seven warning signs that your IBM i integrations may be creating unnecessary technical debt, along with practical ways to address them.

What Is IBM i Integration Technical Debt?

IBM i integration technical debt refers to the additional complexity, maintenance effort, and operational risk created by integration methods that become difficult to support or extend.

Common examples include:

• Custom point-to-point interfaces
• Undocumented RPG integration programs
• Repetitive file transfers
• Manual data entry between systems
• Duplicate integration logic
• Outdated authentication methods
• Inconsistent API implementations
• Limited error handling and monitoring

These approaches are not automatically problematic. Some remain appropriate for specific workloads.

Technical debt becomes an issue when maintaining existing integrations consumes more time and resources than the value they provide.

As organizations connect IBM i with cloud applications, mobile platforms, eCommerce systems, and AI solutions, managing this complexity becomes increasingly important.

1. Every New Application Requires Another Custom Integration

One of the clearest signs of IBM i integration technical debt is the need to build a completely new interface whenever another application requires business data.

Imagine an organization where:

• An eCommerce platform needs inventory availability.
• A CRM requires customer information.
• A mobile application needs product pricing.
• A customer portal needs order status.

Without a standardized integration architecture, each requirement may result in a separate custom program or interface.

Over time, the organization develops multiple connections that perform similar functions.

Why This Creates Problems

Custom point-to-point integrations can increase:

• Development time
• Maintenance requirements
• Testing complexity
• Security management
• Dependency risks

A change to an IBM i application may require updates across several separate integrations.

How to Fix It

Start building reusable business APIs.

Instead of creating multiple inventory interfaces, develop a secure API that provides inventory availability to approved applications.

For example:

Get Inventory Availability API

This capability could serve an eCommerce website, customer portal, mobile application, and other connected systems.

A reusable API reduces duplicated integration logic and creates a consistent interface for future applications.

2. Critical Business Processes Depend on Manual File Transfers

Batch processing remains an important part of many IBM i environments.

However, problems arise when processes requiring timely information depend on scheduled file transfers or manual intervention.

For example, an organization might export inventory data from IBM i every evening and upload it to an eCommerce platform.

During the day, customers may see inventory information that no longer reflects actual availability.

Why This Creates Problems

Delayed synchronization can contribute to:

• Inaccurate inventory information
• Order processing delays
• Manual reconciliation
• Customer service issues
• Duplicate data entry
• Operational inefficiencies

How to Fix It

Evaluate which business processes would benefit from API-driven or event-driven integration.

For example, a secure inventory API could provide current availability when the eCommerce platform requests it.

An event-driven workflow could notify connected systems when inventory changes.

Not every batch process needs to be replaced. The goal is to identify situations where delayed information creates measurable business problems.

Related Reading: Event-Driven IBM i Integration: Moving Beyond Batch Processing in 2026

3. Only One Developer Understands an Important Integration

Many IBM i environments contain valuable institutional knowledge developed over decades.

However, integration processes can become difficult to maintain when their design and operation are understood by only one employee.

This might include:

• Custom RPG programs
• Legacy web services
• Scheduled integration jobs
• Specialized data mappings
• Undocumented dependencies
• Manual recovery procedures

When that individual is unavailable, troubleshooting or modifying the integration becomes more difficult.

Why This Creates Problems

Knowledge concentration can result in:

• Longer troubleshooting times
• Delayed development projects
• Increased operational risk
• Difficult employee onboarding
• Higher support costs

How to Fix It

Document critical integrations and establish repeatable development practices.

Important documentation should include:

• Business purpose
• Application dependencies
• Data formats
• Authentication requirements
• Error handling
• Recovery procedures
• Ownership

Standardized APIs can also make IBM i capabilities easier for developers outside the RPG team to consume.

The objective is not to eliminate specialized IBM i knowledge, but to make that knowledge more accessible and sustainable.

4. Integration Errors Are Discovered by Customers First

An integration may appear healthy because the IBM i server is running and scheduled jobs are completing.

But that does not guarantee every business transaction has succeeded.

Consider an order integration that encounters an error while communicating with a shipping platform.

If the failure is not detected, employees may only discover the problem when a customer asks why their shipment has not been processed.

Why This Creates Problems

Limited monitoring can lead to:

• Undetected transaction failures
• Delayed order processing
• Missing updates
• Inconsistent data
• Increased support requests
• Longer incident resolution times

How to Fix It

Introduce integration monitoring and observability.

Organizations should track:

• API availability
• Response times
• Error rates
• Failed transactions
• Authentication failures
• Dependency performance
• Business transaction completion

Monitoring should provide visibility into the complete integration workflow rather than only the individual server or endpoint.

Related Reading: IBM i API Monitoring: How to Keep Modern Integrations Reliable

5. Developers Repeatedly Recreate the Same Business Logic

IBM i applications often contain trusted business rules for pricing, inventory, order validation, and customer management.

Technical debt can develop when these rules are recreated in multiple applications.

For example, an organization might calculate customer pricing separately in:

• Its IBM i order-entry application
• An eCommerce platform
• A mobile sales application
• A customer portal

Each implementation may initially produce the same result.

But when pricing rules change, every implementation must be updated.

Why This Creates Problems

Duplicated business logic increases the risk of:

• Inconsistent calculations
• Maintenance overhead
• Testing requirements
• Application errors
• Conflicting business information

How to Fix It

Keep trusted business logic centralized where appropriate and expose it through reusable APIs.

Instead of recreating customer-specific pricing rules, connected applications can call an IBM i pricing API.

The IBM i application performs the calculation using existing RPG business logic.

The API returns the approved result.

This allows organizations to preserve proven processing while extending its availability to modern applications.

6. Integration Security Is Inconsistent

As organizations add new integrations, security practices may evolve unevenly.

Older interfaces may use authentication methods that differ from newer APIs.

Some integrations may have limited logging, inconsistent permissions, or credentials that are difficult to manage.

Why This Creates Problems

Inconsistent security can create:

• Unnecessary access privileges
• Credential management challenges
• Limited auditability
• Difficult compliance reviews
• Increased operational risk

How to Fix It

Establish consistent integration security standards.

These should address:

• Authentication
• Authorization
• Encryption
• Least-privilege access
• Credential management
• Input validation
• Logging
• Monitoring

Organizations should also maintain an inventory of production APIs and their consumers.

API governance becomes particularly important as the number of connected applications grows.

7. Integration Projects Take Longer Than Expected

One of the most expensive forms of technical debt is the time required to implement seemingly straightforward changes.

A business team might request:

“Can we make customer order status available in our mobile application?”

The requirement sounds simple.

But the development team may discover that the necessary information is buried inside an interactive RPG program, depends on several undocumented processes, or requires a custom interface.

What should be a manageable integration project becomes a much larger development effort.

Why This Creates Problems

Complex integrations can slow:

• Customer-facing improvements
• Cloud adoption
• Application modernization
• Business automation
• AI initiatives
• New partner connections

How to Fix It

Adopt an API-first approach to exposing reusable IBM i business capabilities.

Begin with high-value functions such as:

• Customer lookup
• Inventory availability
• Order status
• Product pricing
• Shipment information
• Account information

As these capabilities become accessible through documented APIs, future integration projects can reuse them.

The objective is to reduce the amount of custom development required for each new application.

How RPG-Based APIs Help Reduce IBM i Integration Technical Debt

For organizations running IBM i, one challenge is introducing modern integration capabilities without unnecessarily expanding the technology stack.

Kato Integrations addresses this through RPG API Express, an API toolkit designed for IBM i developers.

RPG API Express enables teams to build and consume web services using RPG, supporting REST and SOAP integrations along with JSON and XML data.

This approach allows organizations to extend existing IBM i applications while continuing to use familiar development skills.

Potential advantages include:

• Reusing existing RPG business logic
• Reducing duplicate integration development
• Connecting IBM i with cloud applications
• Simplifying access to business functions
• Supporting incremental modernization
• Making integration capabilities reusable

Modernization does not have to begin with a complete application rewrite.

It can begin by making one important business function easier to access.

How to Prioritize IBM i Integration Technical Debt

Not every integration problem needs to be addressed immediately.

A practical strategy begins by identifying the integrations creating the greatest business impact.

Evaluate each integration using four questions.

Business Impact

Does the integration affect customers, orders, inventory, revenue, or other important operations?

Maintenance Effort

How much development or support time does the integration require?

Operational Risk

What happens if the integration fails or the employee responsible for it becomes unavailable?

Reusability

Could modernizing the integration create a reusable capability for other applications?

Projects with high business impact, significant maintenance costs, and strong reuse potential are often good candidates for modernization.

A Practical 90-Day IBM i Integration Improvement Plan

Organizations can begin reducing integration technical debt without launching a large transformation initiative.

Days 1–30: Assess

• Inventory critical integrations.
• Identify manual processes.
• Document dependencies.
• Review integration failures.
• Identify duplicated business logic.
• Evaluate security and monitoring gaps.

Days 31–60: Prioritize

• Select one high-value integration.
• Define the business problem.
• Identify the RPG programs involved.
• Determine whether a reusable API is appropriate.
• Establish security and documentation requirements.

Days 61–90: Implement and Measure

• Develop or improve the integration.
• Test the business process.
• Implement monitoring.
• Document the interface.
• Measure improvements in processing time, reliability, or maintenance effort.

The goal is to establish a repeatable modernization process that can be applied to additional integrations.

Looking Ahead: Kato Integrations at IBM TechXchange 2026

As organizations evaluate how to reduce integration complexity and prepare their IBM i environments for 2027, these conversations will continue at IBM TechXchange 2026.

With the conference less than a week away, Kato Integrations is preparing to join the IBM i community in Atlanta.

Kato Integrations is proud to sponsor IBM TechXchange 2026, taking place October 26–29 in Atlanta, Georgia.

Attendees can connect with the Kato team in the COMMON Hub within the Sandbox Expo to discuss practical IBM i integration and modernization challenges.

Whether your organization is working to eliminate manual file transfers, develop RPG-based APIs, connect cloud applications, or simplify existing integrations, we’d welcome the opportunity to talk.

Visit Kato Integrations at IBM TechXchange

Event: IBM TechXchange 2026

Dates: October 26–29, 2026

Location: Georgia World Congress Center, Atlanta, Georgia

Kato Integrations: COMMON Hub Sponsor

Event Website: https://www.ibm.com/events/techxchange

Frequently Asked Questions About IBM i Integration Technical Debt

What is IBM i integration technical debt?

IBM i integration technical debt refers to the ongoing maintenance costs, complexity, and operational risks created by integrations that become difficult to support, modify, or extend.

What causes integration technical debt?

Common causes include custom point-to-point interfaces, undocumented programs, duplicated business logic, manual data transfers, inconsistent security, and limited monitoring.

Do legacy IBM i integrations always need to be replaced?

No. Some existing integrations continue to meet business requirements effectively. Modernization should focus on processes where complexity, maintenance effort, or delayed information creates measurable problems.

How can APIs reduce IBM i integration technical debt?

APIs provide reusable, documented interfaces to IBM i business capabilities. They can reduce duplicated development and simplify connections with cloud, mobile, web, and third-party applications.

Can RPG developers build modern APIs?

Yes. RPG-based API tools allow IBM i developers to build and consume web services while continuing to use their existing RPG expertise.

What should an organization modernize first?

Start with integrations that have high business impact, frequent failures, significant manual work, limited documentation, or strong potential for reuse.

Does reducing integration technical debt require replacing IBM i?

No. Organizations can preserve IBM i applications and RPG business logic while improving the integration methods used to connect them with other systems.

Where can I meet Kato Integrations at IBM TechXchange 2026?

Kato Integrations will participate as a sponsor in the COMMON Hub at IBM TechXchange 2026 in Atlanta, October 26–29.

Final Thoughts

IBM i integration technical debt rarely appears overnight.

It develops gradually as organizations add applications, build interfaces, introduce workarounds, and respond to changing business requirements.

Over time, those decisions can make integration more complicated than necessary.

The solution is not automatically to replace existing systems.

It is to identify where complexity creates business problems and introduce more consistent, reusable integration methods.

By combining trusted RPG business logic with secure APIs, documentation, monitoring, and thoughtful architecture, organizations can reduce integration technical debt while preparing for future applications and technologies.

The goal is not simply fewer integrations. It is an IBM i environment where every new connection becomes easier to build, manage, and maintain.

If you’re attending IBM TechXchange 2026 next week, connect with Kato Integrations in the COMMON Hub to discuss how your organization can simplify IBM i integration and prepare for what’s next.