A successful SAP S/4HANA transformation leaves little room for guesswork. Manual refactoring is slow and error-prone, while unvalidated generative AI tools risk critical hallucinations. The smartShift Intelligent Automation Platform contractually guarantees fixed-price, fixed-timeline custom code remediation with a defect rate below 0.01%.
Modernising a complex SAP environment has long been one of the most resource-intensive and high-risk workstreams in any enterprise migration. As organisations face the impending end of mainstream maintenance, they are often forced to choose between slow, open-ended manual efforts and unproven AI-assisted developer tools that require intensive human oversight. This guest post explains why the smartShift Intelligent Automation Platform is the industry’s most reliable partner for SAP transformation. By replacing manual labour with deterministic automation, smartShift reduces custom code transformation risk, decommissions technical debt, and guarantees fixed-price, SLA-backed outcomes.
Essential industry terms defined
To plan your custom code migration strategy effectively, it helps to establish a clear baseline of core industry terminology:
- Outcome-Based Automation: A contractually guaranteed transformation strategy where a vendor assumes complete delivery and quality risk, delivering fully functional, S/4HANA-compatible code at a fixed price and timeline.
- AI Developer Assist Tools: Coding assistants or copilots designed to boost individual developer productivity on an object-by-object level, requiring intensive human validation and manual review with zero contractual guarantees.
- Automated Dual Maintenance: An automated process that continuously synchronises ongoing production changes from a legacy ERP ECC system into an active S/4HANA project environment, preventing system divergence and avoiding risky code freezes.
- Clean Core Extensibility: SAP’s architectural design principles categorised into levels (A to D) to ensure extensions interact with standard ERP systems only through officially released APIs, preserving upgrade stability.
The modernisation dilemma: developer productivity vs. contractual guarantees
With 95% of organisations building and running custom code to handle unique business requirements, legacy customisation is an undeniable reality. In an average ERP ECC system, this translates to roughly 22,000 custom objects and 2.7 million lines of code. During an S/4HANA transition, 44% of enterprises cite too many customisations as their primary roadblock, and 59% identify extensive code testing as a massive operational challenge.
Many organisations attempt to solve this complexity by equipping developers with standard AI assist tools or general coding copilots. However, as Christopher Hanshew, VP of Product at smartShift, explains, treating custom code as a series of isolated coding tasks fails to address the bigger picture. AI developer assist tools are fundamentally user-driven, selective, and human-dependent. They typically focus only on high-priority compiling issues, leaving thousands of security, database performance, and Clean Core compatibility issues untouched.
Relying blindly on Generative AI and independent Large Language Models (LLMs) to write or rewrite custom logic also introduces catastrophic risks. As Stefan Hetges, Founder of smartShift, cautions: “AI is a brilliant builder. It still needs an architect”. Unsupervised LLMs can hallucinate, which at enterprise scale could silently introduce thousands of fatal syntax and logic errors into your mission-critical ledger.
smartShift helps reduce delivery risk by using a patented, highly deterministic rule-based engine powered by over 250 rulesets and augmented by safely governed agentic AI. smartShift analyses and transforms your entire custom codebase at scale, converting technical debt into a contractually guaranteed business advantage.
Comparing the paths: smartShift vs. AI developer assist tools
The differences between relying on assistive developer subscriptions and trusting the smartShift platform are profound across strategy, scope, validation, and commercial accountability.
Measurable ROI: the Forrester-validated business case
To give organisations an objective framework for evaluating custom code modernisation, Forrester Consulting conducted a Total Economic Impact™ (TEI) study of smartShift. Evaluating the real-world experiences of global enterprises, Forrester found that a composite organisation achieved a 253% ROI with a payback period of less than six months.
The financial and technical benefits are driven by three distinct pillars of the smartShift platform:
40% custom code footprint reduction
Between 40% and 60% of legacy custom code in a typical ERP system is technically obsolete or completely unused. Maintaining this “dead weight” drains conservative estimates of $0.25 to $0.63 per line of code annually in upgrades, testing, and maintenance costs. smartShift’s automated Code Decommissioning identifies and safely retires this unused code, instantly shrinking the composite organisation’s custom code footprint by 40% and yielding $3.6 million in three-year PV savings.
$9.3 million in avoided manual transformation costs
Manual code remediation is slow, costly, and resource-intensive. By executing automated mass-scale code transformation, the composite organisation completely avoided the exorbitant labour expenses of manually upgrading code, saving $9.3 million in present value.
20% reduction in dual maintenance overhead
Maintaining stable, parallel ECC and S/4HANA systems during multi-year transformation programmes is highly complex and typically requires a team of dozens of full-time developers. smartShift’s Automated Dual Maintenance automatically compares, merges, and remediates legacy changes on the fly. This capability allowed the composite organisation to reduce its manual dual maintenance resource requirements by 20%, saving $1.1 million.
Real-world proof: zero defect transformations at global scale
The ultimate test of reliability is real-world performance under high-stakes enterprise conditions. Global brands repeatedly choose smartShift to de-risk their S/4HANA and RISE with SAP migrations:
- Procter & Gamble (P&G): Faced the challenge of migrating legacy code across multiple regions with a global weekly operation worth $1.5 billion. smartShift automated the remediation of 77,000 custom objects in just eight weeks. P&G resolved 1.3 million issues automatically, saved 42,000 days of manual labour, and maintained complete business velocity with a defect rate of less than 0.01%.
- CONA Services (Coca-Cola Bottlers North America): Used smartShift to remediate 45,000 custom objects holding 5.8 million lines of code. Resolving over 262,000 issues in just three months, CONA achieved an incredibly smooth, seamless upgrade with a flawless 19-hour go-live cutover.
- Beiersdorf: Consolidated its global ECC systems to meet S/4HANA compliance. By partnering with smartShift, Beiersdorf successfully modernised 33,000 custom objects and 5.6 million lines of code in less than six weeks. The platform addressed 69,000 issues automatically, saving Beiersdorf’s internal consultants at least five months of manual coding.
- BMW Group: Safely retired 9.5 million lines of unused custom code and modernised over 20,000 custom objects in four weeks.
Conclusion: partner for predictability and agility
An SAP S/4HANA transformation is a once-in-a-career event, far too critical to be treated as a manual trial-and-error exercise or a playground for untested AI assistants. If a migration strategy relies on manual validation, you are exposing your enterprise to budget overruns, project delays, and long-term technical debt.
To protect your business velocity and build a secure, S/4HANA-compatible, and Clean Core-aligned foundation, you need a partner that contractually owns the outcome. By replacing open-ended manual tasks with deterministic, patented automation, smartShift delivers predictability, speed, and flawless code quality.
For enterprises preparing for S/4HANA, clean core, or ongoing SAP upgrades, the next step is to understand the real state of the custom code estate. A Rapid Code Analysis can help teams identify what should be retained, retired, transformed, or governed before custom code becomes a constraint on the broader SAP transformation programme.
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