Software Engineer for AI-Centric Applications / AI Lead

Our client, a leading organisation operating within the critical infrastructure and energy sector, is looking for an experienced Software Engineer to join a software engineering team focused on developing innovative AI-powered applications. This role combines strong software engineering expertise with hands-on experience in Large Language Models (LLMs), Retrieval-Augmented Generation (RAG), AI assistants, and agentic workflows. You will contribute to the design, development, evaluation, and optimisation of production-grade AI solutions that are scalable, secure, maintainable, and deliver real business value.

This is a hands-on engineering position where you will help shape technical direction while actively building and improving AI-driven applications.

Key Responsibilities: Design and develop AI-powered applications leveraging LLMs, RAG architectures, and agent-based workflows. Build and maintain backend services, APIs, and integrations supporting AI-centric solutions. Design and optimise retrieval pipelines, including chunking strategies, embeddings, vector and hybrid search, metadata filtering, and re-ranking mechanisms. Integrate and orchestrate LLM APIs and AI frameworks to create reliable and efficient workflows.

Implement testing, monitoring, evaluation, and observability practices for AI applications. Define and promote best practices around tool usage, human-in-the-loop processes, agentic behaviour, and AI governance and reliability. Collaborate closely with software engineers, product teams, and business stakeholders. Support technology selection by evaluating quality, cost, latency, maintainability, and security requirements. Investigate and resolve challenges such as hallucinations, retrieval issues, latency bottlenecks, cost inefficiencies, and inconsistent AI outputs.

Required Skills & Experience: Fluent in English (spoken and written). Minimum 5 years of experience as a Full Stack Developer or Software Engineer. Hands-on experience with AI frameworks such as LangGraph, LangChain, Semantic Kernel. Strong experience designing and maintaining production-grade applications, including testing strategies, logging and monitoring, CI/CD pipelines, and deployment practices. Good understanding of AI application evaluation methodologies, including test datasets, quality metrics, regression testing, and user feedback loops.

Experience with cloud-native application development. Security-focused mindset when working with sensitive or business-critical data. Strong communication skills with the ability to explain technical trade-offs to both technical and non-technical stakeholders. Ability to assess when AI-driven approaches are appropriate and when traditional deterministic solutions are a better fit.

Nice to Have: Experience with Retrieval-Augmented Generation (RAG), embeddings, vector databases, and retrieval optimisation techniques. Knowledge of MCP (Model Context Protocol), A2A communication, tool calling, and multi-agent systems. Experience with AI observability and evaluation platforms. Familiarity with Microsoft Azure. Experience within the Microsoft AI ecosystem, including Semantic Kernel, Microsoft Agent Framework, Microsoft Foundry, and Microsoft 365 Agents SDK.

Development experience in .NET/C# and/or Python. Experience with enterprise search platforms. Previous experience in regulated, security-sensitive, or large enterprise environments.

Profile: The ideal consultant is comfortable working across software engineering, AI integration, application evaluation, security, and production readiness. You are capable of rapidly developing proof-of-concepts and MVPs while applying the engineering discipline required to create scalable, maintainable, and enterprise-ready solutions.

Practical Information: Location: Brussels area.

Hybrid Working Model: A minimum onsite presence of 2 days per week is required. For part-time consultants, this requirement is applied proportionally to the agreed work schedule.

Work Authorization Requirements: Candidates intending to work in Belgium must have a valid work permit authorising employment in Belgium and a valid residence permit granting the right to reside in Belgium.