Are you looking for a career move that will put you at the heart of a global financial institution? Then bring your skills in analysis, application development, problem solving and communication to Source to Pay Solutions Technology group. By Joining Citi, you will become part of a global organisation whose mission is to serve as a trusted partner to our clients by responsibly providing financial services that enable growth and economic progress. **Team/Role Overview** Source to Pay Solutions Technology group is part of COO (Citi Operating Office) Technology organization supporting Citi Operating Office business function and its enterprise-wide transformation agenda to achieve improvements across risk management, controls, data governance, AI adoption, and process re-engineering by delivering scalable, secure, and modern technology solutions. Based in Belfast, the team partners closely with businesses and technology stakeholders to build, manage, and modernize multiple Source to Pay applications, playing a key role in translating strategic transformation priorities into measurable operational outcomes. **What you'll do** Senior Application Development Lead (Gen AI) is a senior level position responsible for * **Set technical direction for Gen AI adoption** across multiple applications or teams, defining reusable patterns, reference architectures, and best practices aligned with enterprise standards. * **Design, integrate, and evolve Gen AI capabilities** (LLMs, APIs, agentic workflows, automation) in business-critical applications, focusing on clear value, reliability, and responsible usage * **Own end-to-end delivery of Gen AI enabled features**, from solution design and implementation through production rollout, support, and continuous improvement * **Collaborate daily with global and regional technology and business teams** to deliver against regulatory, risk, and transformation priorities * **Apply agile engineering practices**, leveraging iterative delivery, pragmatic architectural decisions, and emerging Gen AI/agentic tooling to accelerate outcomes * **Provide technical leadership and mentorship** through hands-on development, code reviews, and design guidance, raising the overall engineering bar * **Ensure solutions meet Citi standards** for security, stability, resilience, and operational control, working closely with architecture, risk, and production support teams * **Continuously assess and improve system quality**, balancing performance, cost, accuracy, and user experience in production Gen AI applications **What we'll need from you** * **Deep expertise in Large Language Models (LLMs)**, including commercial and open-source models (e.g., OpenAI, Gemini, Claude, Llama), and selecting the right model for use case, cost, and performance constraints * **Hands-on experience building Gen AI applications using modern frameworks** such as LangChain, LangGraph, LlamaIndex, and Hugging Face, including agentic and multi-step workflows * **Proven experience designing and implementing Retrieval-Augmented Generation (RAG) systems**, including vector databases (pgvector, Pinecone, Weaviate, FAISS, etc.) and advanced retrieval strategies (hybrid search, re-ranking, metadata filtering) * **Strong understanding of prompt engineering, workflow design, and Gen-AI optimization**, balancing latency, cost, quality, and accuracy trade-offs in production systems * **Solid grounding in ML/DL concepts**, with hands-on experience applying frameworks such as **PyTorch and/or TensorFlow**, including embeddings and model fine-tuning where appropriate * **Experience deploying and operating production Gen AI systems**, leveraging **Docker, cloud-native architecture, production APIs, and monitoring/observability tools**, with an emphasis on reliability and scalability * **Strong hands-on software engineering skills**, including **Python, FastAPI, async programming patterns**, and building high-performance AI-powered APIs * **Understanding of AI system evaluation, safety, and governance**, including hallucination handling, guardrails, feedback loops, and responsible AI considerations, combined with the ability to work independently and communicate effectively in agile environments **What we can offer you** This role offers the opportunity to shape how Generative AI is responsibly adopted across critical enterprise workflows, influencing both technology strategy and business outcomes. You’ll work at the intersection of platform engineering, AI governance, and large-scale transformation, with clear visibility and impact across the organization. We work hard to have a positive financial and social impact on the communities we serve. In turn, we put our employees first and provide the best-in-class benefits they need to be well, live well and save well. By joining Citi Belfast, you will not only be part of a business casual workplace with a hybrid working model (up to 2 days working at home per week), but also receive a competitive base salary (which is annually reviewed), and enjoy a whole host of additional benefits such as: * Generous holiday allowance starting at 27 days plus bank holidays; increasing with tenure * A discretional annual performance related bonus * Private medical insurance packages to suit your personal circumstances * Employee Assistance Program * Pension Plan * Paid Parental Leave * Special discounts for employees, family, and friends * Access to an array of learning and development resources Alongside these benefits Citi is committed to ensuring our workplace is where everyone feels comfortable coming to work as their whole self every day. We want the best talent around the world to be energized to join us, motivated to stay, and empowered to thrive. **Sounds like Citi has everything you need? Then apply to discover the true extent of your capabilities.** ------------------------------------------------------ **Job Family Group:** Technology ------------------------------------------------------ **Job Family:** Applications Development ------------------------------------------------------ **Time Type:** Full time ------------------------------------------------------ **Most Relevant Skills** Please see the requirements listed above. ------------------------------------------------------ **Other Relevant Skills** For complementary skills, please see above and/or contact the recruiter. ------------------------------------------------------ _Citi is an equal opportunity employer, and qualified candidates will receive consideration without regard to their race, color, religion, sex, sexual orientation, gender identity, national origin, disability, status as a protected veteran, or any other characteristic protected by law._ _If you are a person with a disability and need a reasonable accommodation to use our search tools and/or apply for a career opportunity review [Accessibility at Citi](#)._ _View Citi’s [EEO Policy Statement](#) and the [Know Your Rights](#) poster._