Senior Auditor

OneSource Consulting; Namen; On-site; EUR 90,000 - 130,000; Full time

Job summary

OneSource Consulting is seeking a Senior Audit & Transformation Architect to lead audits and modernization efforts for tax information systems within the CS AIR service center. The role focuses on independent assessment of technical debt and architectural risks, and on informing investment and transformation decisions.

The candidate will define target architectures, evaluate dependencies, and challenge external providers to ensure compliant, scalable solutions in a regulated environment.

Qualifications

• At least ten years of relevant experience in application architecture, including audit, transformation or governance functions.
• At least three significant architectural audits or complex systems transformations.
• Experience in modernization trajectories and presenting to decision bodies.
• Experience challenging service providers and following up on recommendations.

Responsibilities

• Carry out technical and architectural audits of existing or proposed solutions.
• Establish objective diagnoses on technical debt, dependencies, performance, security, and maintainability.
• Define target architectures, transformation scenarios and migration trajectories.
• Contribute to risk analyses to inform governance decisions.
• Support implementation of recommendations and verify effective execution.
• Articulate options, trade-offs, risks and costs to stakeholders.

Skills

Technical debt analysis

Architectural risk assessment

Transformation & modernization

Enterprise Java & APIs

Job description

JOB TITTLE : SENIOR AUDIT & TRANSFORMATION ARCHITECT

LANGUAGE : ENGLISH, FRENCH

DURATION : 04/01/2027 - 03/01/2028

JOB DESCRIPTION

Background and purpose

• Within the Integrated Accountable Application (CS AIR) Service Center of Client, the Senior Audit & Transformation Architect is involved in the DES program and, more broadly, in the evolution of the tax information system.
• The purpose of the mission is to provide independent expertise in the audit and transformation of the tax application portfolio. It aims to assess the robustness, relevance and sustainability of existing or future solutions, to control technical debt and architectural risks, and to inform investment and transformation decisions.
• The Senior Audit & Transformation Architect defines realistic and controlled trajectories in order to sustainably improve the resilience, performance, security, maintainability, operability and scalability of the information system. He acts as a referent for management, architects, program managers, business lines, technical teams and external partners.

Main activities

• Carry out technical and architectural audits of existing solutions, under development or proposed by service providers.
• Establish objective diagnoses on technical debt, critical dependencies, structural limitations, performance, resilience, security, maintainability and operability.
• Evaluate the alignment of architectures with business objectives, regulatory constraints and SPW Digital architecture principles.
• Identify and prioritize architectural risks as well as their business, technical, budgetary and operational impacts.
• Define target architectures, transformation scenarios, and migration or modernization trajectories.
• Carry out impact, opportunity and risk analyses in order to inform the decisions of governance bodies.
• Challenge the choices and estimates proposed by external service providers.
• Conduct or contribute to architectural reviews and formalize decisions, conditions, reservations and action plans.
• Support the teams in the implementation of the recommendations and verify their effective consideration.
• Measure the results obtained and adapt recommendations when the findings, constraints or priorities change.
• Contribute to the analysis of complex technical incidents when their causes may be architectural.
• Clearly articulate options, trade-offs, risks, costs and consequences to facilitate decisions.

Minimum experience expected

• At least ten years of relevant experience in application architecture, including several years in audit, transformation or architectural governance functions.
• At least three significant architectural audits, technical debt diagnoses or complex systems transformations.
• Demonstrated experience in defining modernization trajectories and presenting them to decision-making bodies.
• Experience in challenging service providers, evaluating solutions and following up on recommendations.
• Experience in a public, regulated or similarly complex environment.
• Audit and architectural diagnostic reports, including findings, evidence, risks and prioritized recommendations.
• Mapping of components, flows, dependencies, obsolescence and risks.
• Existing and target architecture folders.
• Modernization roadmaps, migration trajectories, and technical debt reduction plans.
• Documented architecture decisions, technical opinions and review reports.
• Action plans with priorities, responsibilities, conditions for success and audit criteria.

SOFT SKILLS

• Ability to distinguish structuring issues from secondary subjects and to prioritize actions.
• Critical thinking, independent judgment and ability to make substantiated recommendations.
• Ability to model, diagram and explain complex systems.
• Ability to present options, trade-offs, risks and costs to technical and non-technical interlocutors.
• Ability to constructively challenge and gain buy-in around architecture decisions.
• Business orientation, solutions and results.
• Rigour, autonomy, method and sense of quality.
• Ability to work in a multidisciplinary environment and manage multiple simultaneous requests.
• Analysis of the application file and answers to specific questions.
• Written test based on an audit and transformation case, followed by an interview for successful candidates.
• The evaluation will focus in particular on the ability to objectify a diagnosis, prioritise risks, compare scenarios and defend a realistic trajectory.

Skills

• Analysis of technical debt, architectural risks and critical dependencies
• Architecture for transformation, modernization and rationalization of the application heritage
• Distributed architecture: microservices, SOA, APIs, integration, and event architectures
• Audit of complex application architectures and objective diagnosis
• Containerization, orchestration, CI/CD, data, and complementary technologies
• Definition of target architectures, transformation scenarios and migration trajectories
• Diagnosis of performance, resilience, security, maintainability and operability
• Enterprise Java environments: Java, Jakarta EE/JEE, Spring Boot and web services
• Architectural governance, journal management and decision support
• Architecture modeling: UML, ArchiMate or equivalent

Questions

• Are you willing to visit the site at least 60% of the time, or even more if necessary?
• (mandatory)
• Do you have a master's degree in computer science or equivalent work experience? Please elaborate
• Present at least three significant architectural audits, technical debt diagnoses or complex systems transformations. Specify your personal responsibility, the findings made, the recommendations made and the decisions made
• Describe an engagement in which your findings led to a major reorientation, redesign, replacement, or transformation of a critical application.
• Present an application transformation trajectory that you have designed and supported: options studied, arbitration criteria, risks, steps, costs and results obtained
• Describe a situation in which you challenged an integrator or service provider and developed a proposed solution.
• Present a distributed or event-driven architecture experience that includes integration, performance, resiliency, or distributed consistency issues
• Do you have significant experience in the public sector or in a comparable regulated environment? Please specify the context and your role
• Do you have any relevant certifications for the assignment? If so, which ones?