Gen AI Engineer: Build Production AI Apps & Agents

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

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.