SAP S/4HANA Brownfield Conversion Technical Architect

Our global manufacturing client is looking to hire a senior SAP technical architect to lead the technical design of a Brownfield conversion from SAP ECC to S/4HANA, working directly with the ERP director. Go-live is November 2027.

Requirements: 15+ years of SAP technical experience, with at least 5 years focused on S/4HANA transformations; Multiple Brownfield conversions delivered end to end; Experience on old, heavily customised SAP systems with many legacy interfaces, multiple modules and country localisations; A track record of producing technical design documents that have passed sign-off with senior and technical stakeholders; Strong expertise in SUM, DMO and downtime optimisation; Experience with SAP Readiness Check, Simplification Item Checks, Custom Code Migration Worklist and ATC; Strong knowledge of S/4HANA, Basis, HANA database architecture, ABAP, integrations and Fiori architecture; Azure experience; Experience with SAP security, transport management and release processes; Knowledge of the S/4HANA extensibility framework, clean core principles and custom code modernisation; Experience working alongside a global SI partner; Strong stakeholder management across PMO, architecture, functional and executive audiences, including defending technical decisions to a CFO; Degree in computer science, IT, engineering or a related discipline.

Responsibilities: Own technically sound SAP design documents that account for legacy code and custom functionality; Design for a system documented since 1996: many modules, country variations and localisations, extensive custom code, numerous old interfaces; Show where technical debt sits and how the conversion removes it, supporting the risk-reduction business case; Secure sign-off from the PMO, architects, ERP director, CFO, SAP-literate functional specialists and implementation partner; Give change management the technical base to explain what the conversion means to each stakeholder; Define end-to-end technical architecture, migration roadmaps and implementation standards; Lead and guide technical workstreams across Basis, infrastructure, integrations, ABAP, Fiori and security; Review and approve solution designs and deployment plans; Assess and document ECC integrations with satellite applications: dependencies, interfaces, data flows, risks; Lead impact assessment across interfaces, middleware, APIs, custom developments and third-party applications; Coordinate remediation with application owners, integration teams and vendors so business-critical integrations survive go-live; Lead custom code assessment and remediation (simplification items, ATC, analysis tools); Set strategy for ABAP adaptation, decommissioning obsolete code and clean core adoption; Drive SUM/DMO execution: sizing, performance, downtime reduction and cutover procedures; Govern migration cycles (sandbox, development, quality, dress rehearsal, production) with checkpoints and quality gates; Design high-availability, scalable, secure Azure landscapes with cloud, infrastructure and security teams; Guide system refreshes, retrofit, transport management and environment strategy; Identify risks and mitigations; support testing, cutover readiness and post go-live stabilisation.