Senior AI Engineer: Hands-On Technical Lead

83zero Limited; Cardiff; On-site; GBP 74,000 - 129,000; Full time

Job summary

83zero Limited is seeking a Senior AI Engineer for a hands-on contract role in Cardiff, with some onboarding time in Cardiff and occasional travel. Inside IR35, £400-£700 per day, you will lead production AI/ML work and shape technical strategy.

You'll write production code, guide engineering teams, evaluate build-versus-buy options, and deploy AI workloads on AWS (Bedrock or SageMaker) while ensuring security, privacy and data residency requirements.

Qualifications

• Strong hands-on experience building production AI/ML systems.
• Excellent software engineering and production coding skills.
• Proven experience deploying AI/ML workloads on AWS.
• Knowledge of Bedrock or SageMaker, alongside services such as S3, IAM and Lambda.
• Practical experience designing and implementing RAG systems.
• Experience with prompt engineering, structured outputs, function calling and tool use.
• Strong understanding of AI evaluation, testing and production monitoring.
• Experience handling security, privacy, tenant isolation and data-residency requirements.
• Ability to explain technical trade-offs, build consensus and lead through influence.

Responsibilities

• Lead and deliver AI-powered features from prototype through to production.
• Write significant production code while guiding other engineers.
• Set the technical direction for AI and machine learning.
• Design and deploy AI/ML workloads using AWS, particularly Bedrock or SageMaker.
• Make and justify architectural and build-versus-buy decisions.
• Evaluate commercial APIs, hosted platforms and self-hosted or open-weight models.
• Balance capability, cost, latency, scalability and data-control requirements.
• Work closely with established product and engineering teams.

Skills

Production AI/ML

AWS deployment

Architectural decisions

Technical leadership

Prompt engineering

RAG systems

Security & privacy

Model evaluation

Tools

Bedrock

SageMaker

S3

IAM

Lambda

Open-weight models

Job description

83zero Limited is seeking a Senior AI Engineer for a hands-on contract role in Cardiff, with some onboarding time in Cardiff and occasional travel. Inside IR35, £400-£700 per day, you will lead production AI/ML work and shape technical strategy.

You'll write production code, guide engineering teams, evaluate build-versus-buy options, and deploy AI workloads on AWS (Bedrock or SageMaker) while ensuring security, privacy and data residency requirements.