Generative AI Engineer

Lorien; Greater London; Hybrid; GBP 65,000 - 110,000; Full time

Job summary

Lorien in London is seeking a software engineer to build, evaluate and operate production-grade AI applications, agents and reusable tooling. This role focuses on AI integration and robust API-driven systems, not just prompt engineering.

You will implement agents, AI-assisted workflows, model integrations, automated evaluations, and guardrails while working hybrid, with on-site three days a week. Open to contract or permanent hire, with IR35 inside.

Qualifications

• Strong software engineer with real experience in APIs, cloud systems, testing and production operations.
• Practical knowledge of LLM application patterns.
• Seniority flexible; solid engineering fundamentals matter more than AI-specific years.

Responsibilities

• Implementing agents, AI-assisted workflows, retrieval systems and model integrations.
• Building deterministic tools and APIs for agents to interact with enterprise systems.
• Developing automated evaluations for quality, safety, reliability and regression detection.
• Implementing guardrails, permissions, traceability, fallback and human-escalation mechanisms.
• Instrumenting solutions for cost, latency, behaviour and business-outcome monitoring.
• Optimising context management, model selection and inference patterns.
• Contributing reusable components, development standards and reference implementations.
• Diagnosing production failures and continuously improving system performance.

Skills

APIs

Cloud systems

Testing

Production ops

LLM patterns

Problem-solving

Consulting background

Tools

REST APIs

Job description

Location: Hybrid - London, 3 days a week

IR35 Status: Inside

Summary:

We're hiring software engineers to build, evaluate and operate production-grade AI applications, agents and reusable tooling. This is a software engineering role specialised in AI, not a prompt-writing or experimentation-only position.

What you'll be doing

• Implementing agents, AI-assisted workflows, retrieval systems and model integrations
• Building the deterministic tools and APIs that agents use to interact with enterprise systems
• Developing automated evaluations for quality, safety, reliability and regression detection
• Implementing guardrails, permissions, traceability, fallback and human-escalation mechanisms
• Instrumenting solutions for cost, latency, behaviour and business-outcome monitoring
• Optimising context management, model selection and inference patterns
• Contributing reusable components, development standards and reference implementations
• Diagnosing production failures and continuously improving system performance

What we're looking for

• A strong software engineer with real experience in APIs, cloud systems, testing and production operations
• Practical, working knowledge of LLM application patterns
• Different seniority levels welcome a solid engineering fundamentals matter more than years of AI-specific experience
• A problem-solver mindset, comfortable working across multiple business areas rather than a single fixed remit
• MBB consulting background (McKinsey, Bain, BCG) is a strong plus, though not required for this role

How this works

• Open to contract or permanent hire
• UK-based candidates: ideally on-site 3 days a week
• Candidates based outside the UK: on-site 3 days every fortnight, with flights and accommodation covered for the right candidate with consulting-firm pedigree
• All contract engagements sit inside the scope of IR35