Citi
Belfast United Kingdom
Senior Application Development Lead – Generative AI (Gen AI)
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
t
o 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
o
rganization
supporting
C
iti
Operating Office
business function
and its
enterprise
‑
wide
transformation agenda
to
ac
hieve
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.
Technology
Applications Development
Full time
Please see the requirements listed above.
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.