Master Enterprise Architecture: Clean Core with SAP
How to move from monolithic ERP to an agile, value-driven architecture with SAP BTP, LeanIX & Signavio – without losing control.
Enterprise Architecture Framework – Overview
This overview shows how to combine well-known frameworks effectively: TOGAF provides the method, ArchiMate the language, BPMN/DMN describe processes and decisions, and the SAP EAF sets guardrails for Clean Core and BTP. The following view helps you pick the right set depending on your goal (transformation, operations, security, modeling).
- EA is no longer documentation but the control center of your transformation – focused on business value.
- Clean Core separates stable standard processes (S/4HANA) from fast innovation (side‑by‑side on SAP BTP).
- The SAP Enterprise Architecture Framework plus Metro Map provide cadence and method for planning and execution.
- LeanIX makes your application landscape transparent; Signavio connects processes and value streams.
- Governance via an Architecture Board enforces principles, guardrails, and clear decision paths.
Who should care?
CIOs, Enterprise Architects, Domain Leads, Program Managers (e.g., RISE with SAP), and Data & Security leaders – anyone who needs to control speed, quality, and cost simultaneously.
Why now? Strategic context
The shift to cloud, SaaS, and event-driven architectures demands new rules. With Clean Core, BTP extensions, and strong governance you reduce upgrade costs, accelerate change, and remain compliant.
Cost
Less customization in the core reduces upgrade and maintenance costs. Rationalization eliminates license and run duplicates.
Agility
Side‑by‑side extensions on BTP deliver fast innovation without touching the core – secure, versionable, scalable.
Compliance
Strong governance, ADRs, and guardrails protect Clean Core principles – auditable and repeatable.
AI Readiness
Clean data models, events, and APIs are the foundation for analytics, GenAI, and automation.
Cloud / RISE
From lift‑and‑shift to transformation: instance strategy, integration strategy, and phases from a single playbook.
M&A
Faster carve‑out and PMI: analyze capability overlap, capture synergies, control risks.
Frameworks Overview
TOGAF
Scope: Full EA lifecycle (ADM).
Strengths: Method, artifacts, governance.
Use for: Structured transformation, architecture process.
ArchiMate
Scope: Modeling business, application & technology layers.
Strengths: Common language, traceability.
Use for: Visualization & impact analysis.
Zachman
Scope: Classification schema.
Strengths: Completeness view.
Use for: Structured documentation, inventory.
BPMN
Scope: Process modeling.
Strengths: Standardized, tool support.
Use for: Signavio processes, automation.
SAP EAF
Scope: SAP‑specific EA guardrails.
Strengths: Clean Core, BTP, integration.
Use for: S/4HANA, RISE, BTP extensions.
ITIL / COBIT
Scope: Operations & controls.
Strengths: Service excellence, auditability.
Use for: Operating model, compliance.
Metro Map
Scope: Non‑linear execution methodology.
Strengths: Synchronizes streams (data, integration, security).
Use for: RISE with SAP programs, complex rollouts.
Quick comparison
TOGAF provides the method, ArchiMate the language, BPMN the process view. SAP EAF grounds all this for S/4HANA, BTP and integration – complemented by ITIL/COBIT in operations.
Frameworks compared (details)
TOGAF SAP fit: Medium
- Method, reference artifacts
- Governance depth
- Less prescriptive in delivery
- Learning curve
- ADM phases
- Principles, roadmaps
- Capability plans
ArchiMate SAP fit: Medium
- Common language
- Traceability, tool support
- Model discipline needed
- No process notation
- Views/viewsheets
- Motivation/realization views
BPMN SAP fit: High
- Standardized, automation‑ready
- Understandable for business
- No EA scope
- Needs governance/versioning
- Process diagrams
- Roles, interfaces
Zachman SAP fit: Low
- Completeness, order
- Inventory view
- No method
- No flow logic
- Matrix Who/What/Where/…
SAP EAF SAP fit: Very high
- Clean Core, BTP
- Integration guidance
- Strong SAP focus
- Guardrails
- Blueprints
- Integration patterns
ITIL / COBIT SAP fit: High
- Service excellence
- Audit/controls
- No architecture target picture
- Processes, policies
- KPIs, controls
Metro Map SAP fit: High
- Synchronize streams
- Expose dependencies
- Discipline required
- No formal standard
- Stations/streams
- Milestone networks
SAFe SAP fit: Medium
- Value streams
- Lean budgets
- Complex, rollout effort
- Program Kanban
- PI plans, ART artifacts
IT4IT SAP fit: Medium
- End‑to‑end delivery model
- Interfaces/contracts
- Focus on IT operations
- Value streams
- Functional components
C4 Model SAP fit: Medium
- Context to code level
- Clarity
- No process/EA scope
- Context/container
- Component/code
DMN SAP fit: Medium
- Clear business rules
- Automatable
- Limited coverage
- Needs governance
- DRD
- Decision tables
DDD SAP fit: Medium
- Bounded contexts
- Clear responsibility model
- Requires strong domain knowledge
- Context maps
- Ubiquitous language
NIST CSF SAP fit: High
- Controls, risk management
- Maturity
- No EA/process focus
- Identify‑Protect‑Detect‑Respond‑Recover
ISO/IEC 42010 SAP fit: Medium
- Foundational principles
- Stakeholders/views
- Abstract
- No implementation method
- Viewpoints
- Views, concerns
Key differences
- TOGAF vs ArchiMate: Method/process vs. language/model. Together they give governance + visualization.
- BPMN vs DMN: Flows vs. decisions. Combine for automated processes.
- SAP EAF vs generic EA frameworks: SAP‑specific guardrails vs. general principles.
- ITIL/COBIT vs SAFe: Operations/controls vs. value‑stream‑based delivery.
- DDD/C4 vs BPMN/ArchiMate: Domain/architecture cut vs. process/EA documentation.
- IT4IT vs NIST CSF: IT delivery model vs. security control framework.
Frameworks comparison (radar)
Clean Core – A complete approach for a stable, maintainable, and future‑proof SAP landscape
The Clean Core approach is a key success factor for any SAP S/4HANA transformation. It ensures that processes, technology, data, and integrations are designed to keep the system stable, leverage cloud innovation, and enable upgrades without costly rework. The following four building blocks together form a complete Clean Core framework.
1. Functional Clean Core
Goal
Keep processes close to SAP standard and harmonize across domains.
What’s included?
- Adopt standard processes instead of building from scratch
- Harmonize variants across all areas
- Define end‑to‑end responsibility per process
- Use SAP Best Practices and Model Company
- Clear fit‑to‑standard decision rules
How do we implement?
- Fit‑to‑standard workshops across business areas
- Leverage preconfigured best‑practice scenarios
- Governance board for deviations from standard
- Process documentation via Signavio or SolMan
Benefits
- Lower complexity
- Faster release cycles
- Reduced defect rate
- Higher end‑to‑end transparency
2. Technical Clean Core
Goal
No changes in the SAP core. Extensions remain upgrade‑safe and cleanly decoupled.
What’s included?
- No modifications in the S/4HANA core
- Use stable APIs instead of direct changes
- Side‑by‑side extensions on SAP BTP
- Modern extension tech (CDS Views, RAP, Key User Extensibility)
- Clear separation between standard and custom
How do we implement?
- Architecture mandates for developers and partners
- Build new functions on BTP or in‑app extensibility
- Governance process for extensions ("Extension Board")
- Document all extensions in an Extension Repository
Benefits
- Upgrade safety over many years
- More stability and fewer incidents
- Leverage SAP innovation immediately
- Reduced technical debt
3. Data Clean Core
Goal
Data quality, model and governance clearly defined and clean.
What’s included?
- Harmonized master data model across business areas
- Clear data owners and data stewards
- Cleanup of legacy, duplicates and inconsistencies
- Use SAP MDG or data governance frameworks
- Rules for data maintenance, permissions and monitoring
How do we implement?
- Establish a data governance board
- Data cleansing campaigns before and during the transformation
- Introduce clear data standards and validation rules
- Proactive data quality metrics (KPIs, dashboards)
Benefits
- Higher automation and fewer manual interventions
- Better decision quality
- Foundation for AI, analytics and process automation
- Fewer errors and questions in daily operations
4. Integration Clean Core
Goal
API‑based, transparent and robust integration architecture.
What’s included?
- Use standardized APIs from SAP API Business Hub
- Avoid point‑to‑point connections
- Event‑driven integration (e.g., SAP Event Mesh)
- Use SAP Integration Suite
- Clear documentation, monitoring and ownership
How do we implement?
- Architecture blueprints and integration guidelines
- Set up an API catalog (versioning, transparency)
- Define Integration Owner roles
- Operate/monitor via SAP Integration Suite
Benefits
- Fewer outages due to robust integration
- Faster onboarding of new systems
- Transparency across interfaces
- Easier maintenance and lower run costs
Why the combination of all four building blocks matters
A Clean Core only works when Functional, Technical, Data, and Integration come together. Isolated actions are not enough. The combination enables:
- a stable S/4HANA landscape
- lower lifecycle costs
- clear ownership
- higher delivery speed
- immediate use of new SAP innovations
- true cloud readiness
Recommendation: Governance & roles
- Process Owner (end‑to‑end responsibility)
- Technical Owner / Lead Architect
- Data Owner / Data Steward
- Integration Owner
- Clean Core Board – central decision body
Guiding principle
Clean Core means: Standard first. API first. Data first. Cloud first. This keeps S/4HANA stable, maintainable, and future‑proof.
Capability Map
Start with “Priority‑1” data objects (e.g., Business Partner, Sales Order) and clear ownership. Add business roles and Fiori apps to ensure real usability.
Reference architecture: layers
Business / Process
- Value streams & capability map guide investments.
- Align Signavio processes to KPIs and roles.
- ADR‑backed decisions remain transparent.
Application / Integration
- S/4HANA as stable core, extensions side‑by‑side on BTP.
- Integration via SAP Integration Suite, events, and APIs.
- LeanIX‑driven rationalization and TCO control.
Data / Analytics
- Shared metadata catalog for core and extension objects.
- Data quality, lineage, self‑service analytics.
- Model ESG metrics through to auditability.
Technology / Cloud / Edge
- Cloud‑first principles, automation, observability.
- Scalable platform services (BTP, storage, runtime).
- Guardrails for cost, security, availability.
Security / Compliance
- IAM, secrets, encryption, least privilege.
- Policies, controls, evidence (e.g., ADR/reviews).
- Regulatory alignment (e.g., AI regulation, NIS2).
AI / MLOps / Governance
- Feature stores, model lifecycle, drift monitoring.
- GenAI with security and IP checks.
- Responsible AI policies & approval flows.
Use cases: Sustainability & M&A
Sustainability management
- Data architecture: model ESG data lineage (capture, calculation, reporting).
- Solution: S/4HANA operational + SAP Sustainability Control Tower for auditable reporting.
- Governance: anchor responsibilities, data quality and evidence.
Mergers & Acquisitions
- Carve‑out: LeanIX inventory to analyze “blast radius” (apps, servers, data) and separation cuts.
- PMI: capability overlap analysis → consolidate duplicates (e.g., HR), prioritize roadmap.
- Risk & pace: guardrails, integration strategy (SAP Integration Suite) and phased plan.
Governance & operating model
Roles & responsibilities (RACI‑light)
- CIO – strategic direction, budget, prioritization.
- Enterprise Architect – principles, target picture, guardrails.
- Data – metadata, data quality, access models.
- Security – policies, controls, risk sign‑off.
- Domain leads – business value, process accountability.
- Works council – co‑determination for roles & work design.
RACI overview
The Architecture Board decides on deviations (ADRs), issues approvals, and enforces principles like “Cloud First”, “Buy before Build”, and “Keep the Core Clean”. Project teams are Responsible, domain leads Accountable, EA/Security Consulted, stakeholders Informed.
Policies & standards
Mandatory guardrails: naming conventions, API standards, event design, data classification, secrets handling, test and release processes, minimum telemetry and documentation (ADRs).
Roadmap: Implementation
Phase 1: Assessment
Inventory with LeanIX, process capture with Signavio, define capability map & instance strategy, Clean Core baseline, identify quick wins & risks.
Phase 2: Pilot
Value‑driver pilot (e.g., pricing logic on BTP), validate reference architecture, automate integration & security, establish the Architecture Board.
Phase 3: Scale
Application portfolio rationalization, rollout per Metro Map, KPI‑driven steering, continuous architecture (automated checks, ADR routine).
Roadmap phases (time/effort profile)
KPIs & value contribution
Release lead time
Run & license costs
Incidents/month
Service/API reuse
Reduction per quarter
Business satisfaction
- Quarterly portfolio reviews and architecture health checks.
- Monthly measurement of lead time, defect density, change failure rate.
- Annual TCO assessment and investment planning by value streams.
- Application rationalization savings (licenses, operations) evidenced.
- Upgrade cost reduction through Clean Core (less customization).
Cadence: Monthly (operational), quarterly (strategic), annually (budget/TCO).
KPI overview
Tools & repositories
Further reading
FAQ
“Clean Core” means keeping the S/4HANA core free of custom code and implementing extensions side‑by‑side on SAP BTP.
- In the core: standard processes, customizing/configuration – no modifications.
- Outside (BTP): custom logic, services, rules, UIs. Integrate via stable APIs/events.
- Guardrails: “Buy before Build”, API‑first, versioned events, ADRs for deviations.
- Anti‑patterns: direct table access, tight coupling, UI bloat without role relevance.
- Measurable: upgrade time ↓, change failure rate ↓, reuse ↑.
Result: faster releases, lower upgrade costs, and clear accountability.
The Metro Map is your non‑linear master plan: it organizes parallel streams and dependencies.
- Streams: data/analytics, integration, security/compliance, processes, applications.
- Artifacts: target picture/reference architecture, migration paths, policies/guardrails, ADRs.
- Cadence: 2–4‑week syncs, joint milestones (“stations”).
- RISE in practice: instance strategy + integration strategy + phased plan from one source.
- Risks: flag critical dependencies early (e.g., master data quality, IAM).
This prevents bottlenecks and keeps multi‑workstream programs on track.
LeanIX focuses on the IT landscape, Signavio on business processes and journeys – together you get end‑to‑end transparency.
- LeanIX: apps, interfaces, TCO/costs, risks, lifecycle, tech debt.
- Signavio: BPMN processes, roles, KPIs, pain points, automation potential.
- Link: process → capability → application/API; impact analysis for changes.
- Practice: align namespaces/IDs, automate imports (CMDB, repos, tickets).
Use LeanIX for portfolio steering and rationalization, Signavio for process improvement and adoption.
Only in justified exceptions – ideally temporary and with a clear rollback plan.
- Allowed: legal requirements, security/audit duties, missing standard functionality.
- Process: ADR with rationale, risk assessment, time limit, exit plan, board approval.
- Control: telemetry/monitoring, regular reviews, evaluate alternatives.
- Priority: first standard/config, then BTP extension, lastly core extension.
The goal remains to remove modifications quickly and return to Clean Core.
The choice depends on compliance, differentiation, and operational needs.
- RISE/SaaS: faster upgrades, more predictable costs; good for standardizable capabilities.
- Private Cloud: more control/isolation; useful with strict requirements or legacy dependencies.
- Decision logic: standard → SaaS; differentiation → BTP/Private Cloud (side‑by‑side).
- Instance strategy: multi‑instance for legal needs, shared services via BTP.
Important: keep Clean Core and implement extensions outside the core.
AI automates cataloging and analysis and supports the target picture – under clear guardrails.
- AI mapping: auto‑assign apps to capabilities, detect redundancies.
- Generative architecture: LLMs suggest target architectures/integration patterns.
- MLOps: versioning, tests, monitoring (drift/quality), approval flows.
- Governance: responsible AI policies, IP/training‑data, auditability.
Use AI to keep EA current – decisions remain with the Architecture Board.
It’s the “single source of truth” for business/technical object definitions – essential for Clean Core.
- Content: business definition, data type, process relevance, data owner, quality rules.
- Priority‑1 objects: e.g., business partner, sales order – define these first.
- Interop: semantic consistency between core and BTP extensions, clear API contracts.
- Governance: change workflow, versioning, approval by Data/EA.
This keeps data flows traceable and AI/analytics use cases robust.
They connect organization, tasks, and Fiori apps – for lean, relevant UIs.
- Mapping: role → tasks/processes → concrete Fiori apps & permissions.
- Benefit: faster onboarding, fewer errors, clear prioritization for extensions.
- Approach: capture roles, consolidate apps, remove excess, test UX.
- Governance: changes via board/RACI; documentation as part of the reference architecture.
This increases adoption and avoids “bloatware” – a core Clean Core principle.