Research Engineer - LLMs & Generative Audio

Harnham; Slough; Hybrid; GBP 108,000 - 132,000; Full time

Benefits offered by this job

Hybrid work model

London-based office

Job summary

Harnham invites applications for a Senior AI Engineer to build production-grade LLM systems and shape a new AI Lab focused on next-generation AI-powered consumer experiences. You will work in a small, high-autonomy team inside a global organisation, collaborating with engineering, product and design on greenfield AI systems.

The role covers tuning tone and output quality, building retrieval and RAG workflows, developing audio-first products with TTS/STT, and shaping evaluation frameworks for

Qualifications

• Experience building production-grade LLM systems.
• Strong track record with retrieval and RAG workflows.
• Proficiency in Python and modern ML tooling.
• Hands-on experience with audio-first AI products and multimodal systems.

Responsibilities

• Build and deploy production-grade LLM systems.
• Design and optimise RAG and retrieval workflows.
• Fine-tune models for tone, style, and output quality.
• Develop audio-first AI products using TTS/STT workflows.
• Build multimodal AI experiences across text, voice, and search.
• Create evaluation frameworks for hallucination and response quality.
• Prototype and iterate rapidly in a greenfield environment.

Skills

LLM systems

Retrieval/RAG

Model fine-tuning

Audio-first AI

Multimodal AI

Evaluation frameworks

Python

HuggingFace

LangChain

TTS/STT

Tools

LangChain

RAG pipelines

TTS/STT tooling

Job description

Do you want to help build the next generation of AI-native content and audio experiences?

Have you built LLM systems where output quality, tone, and trust genuinely mattered?

Are you ready to work on multimodal AI products spanning text, voice, and conversational interfaces?

A globally recognised media and information business is building a brand-new internal AI Lab focused on next-generation AI-powered consumer experiences.

This is a small, high-autonomy innovation team operating like a start-up inside an established international organisation.

The team is exploring how conversational AI, retrieval systems, audio experiences, and multimodal generation can reshape how users interact with content and information products. You'll work closely with engineering, product, and design stakeholders on genuinely greenfield AI systems.

This Senior AI Engineer role is focused on building production-grade LLM systems across fine-tuning, retrieval, summarisation, evaluation, and audio-first AI experiences. It's a hands-on role with strong ownership and the opportunity to influence the technical direction of a newly formed AI Lab.

Key Responsibilities

• Build and deploy production-grade LLM systems
• Design and optimise RAG and retrieval workflows
• Fine-tune models for tone, style, and output quality
• Develop audio-first AI products using TTS/STT workflows
• Build multimodal AI experiences across text, voice, and search
• Create evaluation frameworks for hallucination and response quality
• Prototype and iterate rapidly in a greenfield environment

Key Details

• Salary: Up to ~£120k base
• Working model: Hybrid (3+ days/week in London)
• Stack: Python, HuggingFace, LangChain, RAG, multimodal AI, TTS/STT, evaluation frameworks
• Sponsorship: To be confirmed