Senior AI Architect & Tech Lead — Hybrid (RAG & ML)

Citigroup Inc.; Belfast City District; On-site; GBP 90,000 - 140,000; Full time

Job summary

Citigroup Inc. is seeking a Lead AI Engineer to shape the technical direction of AI initiatives within Citi's global technology team.

You will mentor engineers and deliver scalable, AI-powered applications that leverage data and automation at scale. In this senior role, you will architect AI systems, guide RAG pipelines, and collaborate with stakeholders to translate complex requirements into robust implementations while upholding security, quality, and performance standards.

Qualifications

• 6–10 years of software or application development experience with delivery of complex projects from design to production.
• Proficiency in Python for application development, data ingestion, and ETL processes.
• Experience building RAG pipelines and agent orchestration frameworks (ADK, LangGraph, LangChain).
• Advanced SQL design and optimization on large datasets.
• Strong understanding of Transformer architecture and production AI systems.
• Evidence of leading technical teams and delivering results in fast-paced environments.
• Clear communication of complex technical concepts to diverse audiences.

Responsibilities

• Architect and develop AI-driven applications and data pipelines using Python, ensuring solutions are scalable and aligned with strategy.
• Lead design and implementation of RAG systems and agent orchestration frameworks.
• Partner with stakeholders across teams to translate requirements into robust technical implementations.
• Define and enforce coding standards, testing practices, and development processes.
• Evaluate technical challenges and develop innovative solutions.
• Coach mid-level engineers and analysts, guiding work allocation and growth.
• Identify and manage technical risks, ensuring security, compliance, and platform integrity.

Skills

Python programming

SQL proficiency

Transformer models

Leadership experience

Communication skills

Education

Master's degree in CS/Engineering

Tools

ADK

LangGraph

LangChain

Llama Index

Neo4j

Job description

Citigroup Inc. is seeking a Lead AI Engineer to shape the technical direction of AI initiatives within Citi's global technology team.

You will mentor engineers and deliver scalable, AI-powered applications that leverage data and automation at scale. In this senior role, you will architect AI systems, guide RAG pipelines, and collaborate with stakeholders to translate complex requirements into robust implementations while upholding security, quality, and performance standards.