Migrate AS/400 to the cloud without stopping the business.
We move your AS/400 (IBM iSeries, RPG, COBOL) onto modern cloud-native architectures, preserving the business logic and network integrations. Strangler pattern, business continuity preserved, rollback at every phase.
What happens today.
The AS/400 (today IBM iSeries) is still the operational backbone of many Italian manufacturing and distribution companies. It works, but: RPG programmers are retiring, maintenance costs grow, integrating it with modern systems takes fragile patches, and business evolution clashes with legacy rigidity.
Migrating an AS/400 is not 'installing a new program'. It's an operational archaeology exercise: discover business logic spread across 20 years of RPG, figure out which parts are actually used, which network integrations (EDI, EDIFACT, SFTP files) are critical. Without a progressive approach, the risk of breakage is huge.
We use the strangler pattern: the new system is introduced module by module, the AS/400 stays operational until each new module is validated in production. No big-bang releases, rollback criteria defined per phase, final decommissioning only after 12+ months of parallel run across the whole surface.
The AS/400 leaves on tiptoes, one module at a time. Not in a Hail-Mary weekend.
The solution, broken into parts.
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Legacy audit: 4-8 weeks
We map the current system: RPG/COBOL programs, DB2 schema, network integrations, team's tribal knowledge. Output: dependency map, modules listed by criticality, realistic migration-time estimate.
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Progressive strangler pattern
We identify the modules with the best cost/benefit ratio and rewrite them first. An API facade exposes the legacy to new modules; as new modules go into production, the AS/400 loses surface area.
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Parallel run + rollback gate
Every migrated module runs in parallel with its legacy counterpart. Automatic reconciliation, alerts on deltas. Only after 4-12 weeks without alerts is cutover decided. Rollback criteria predefined for every phase.
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Final decommissioning + handover
The AS/400 is kept read-only for 12+ months after the final cutover, as a historical fallback. Only then is definitive decommissioning considered. Complete documentation to the client, internal-team training, operational support for the first 6 months.
The typical profiles who benefit.
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Manufacturing with AS/400 + legacy MES
Italian manufacturing companies (mechanical, plastics, food) with AS/400 in production for decades, integrated with MES, labelling machines, warehouse systems. Typical size: 50-500 employees.
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Distribution with legacy RPG ERPs
Wholesalers, distributors, retailers with '90s/2000s RPG ERPs, customer EDI integrations, multi-warehouse. The legacy is solid but can't integrate with e-commerce, marketplaces, modern warehouse systems.
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Finance with peripheral mainframe systems
Financial institutions with RPG/COBOL systems peripheral to the core banking. Progressive migration to reduce technical debt without touching the regulated core.
Transparency on what the client does.
Before we start we need a few accesses and decisions. All reasonable, no surprise asks.
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Technical access
- Read access to AS/400 (RPG/COBOL source code, DB2 schema, configurations)
- Access to integrated systems (EDI partners, network systems, MES)
- Isolated test environment (we provide it if you don't have one)
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Knowledge sharing
- Internal point-of-contact who knows the current system (even part-time)
- Existing documentation, even fragmentary
- History of significant changes over the last 5 years
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Operational decisions
- Priority list of modules to migrate (based on business value)
- Operational constraints (untouchable windows, tax deadlines, seasonal peaks)
- Target cloud (AWS, Azure, GCP, OVH, modern on-prem)
Indicative numbers, not quotes.
- TIME
- Initial audit 4-8 weeks. Full migration typically 12-24 months depending on the complexity of the existing code and the level of customization.
- COST
- Audit €15,000-40,000. Full migration €150,000-600,000+ depending on scope. Reliable estimates only after the audit.
- MODEL
- Audit on fixed milestone. Migration in phases with separate milestones per module, possibility to stop at every phase without penalty.
Indicative numbers. For an accurate quote, let's talk.
Answers to the most common questions.
How long does an AS/400 migration really take?
Between 12 and 24 months for a medium system (50-200 users, RPG with 10-20 years of stratification). Projects with simple architecture and few customizations finish in 6-9 months; systems with years of stratification and multiple integrations require 18-24 months. The 4-8 week initial audit estimates the real timeline.
Can we keep using the AS/400 while you work?
Yes, and that is exactly what happens. The strangler pattern keeps the AS/400 fully operational throughout the migration. Modules are migrated one at a time, in parallel run with the legacy, with automatic reconciliation. The final cutover happens only after 12+ months of incident-free parallel run.
RPG programmers are retiring. How do you handle knowledge transfer?
The initial audit is exactly for that: mapping tribal knowledge before it is lost. We work four-handed with your senior programmers (even part-time) to extract real business logic from the code and from their heads before rewriting it. We document everything, no black knowledge.
What happens to historical data during the migration?
All historical data is migrated with automatic pre/post-migration consistency checks. For very large datasets (>10TB) we use incremental differential migration. We keep AS/400 read-only access for 12+ months post-cutover as a historical fallback, before considering definitive decommissioning.
How does the cost compare to keeping the AS/400?
The investment is significant (range €150k-600k) but must be weighed against the total cost of keeping the AS/400: IBM licenses, hardware, RPG programmers (rising cost due to scarcity), accumulated technical debt, missing integrations that throttle growth. Typical break-even 4-7 years post-cutover.
Recognize your case?
Write a couple of lines about your context. We'll reply within 24-48 hours with an initial assessment and a first orientation on time and cost.
Let's talk