Senior AI Engineer – Generative AI & LLM Lab (Hybrid UK)

167 Solutions; Greater London; Hybrid; GBP 100,000 - 140,000; Full time

Job summary

167Solutions is partnering with a leading global organisation to recruit an experienced AI / LLM Engineer for an exciting new Generative AI Innovation Lab. You’ll join a small, highly skilled team building, fine-tuning and deploying LLM-powered systems focused on tone, retrieval-augmented generation and multimodal AI, including audio and voice technologies.

As an early engineer, you’ll shape direction with product and design leadership and own end-to-end delivery from prototype to production for

Qualifications

• 3+ years’ experience developing solutions using LLMs, NLP or Generative AI technologies.
• Hands-on experience with leading models and platforms such as OpenAI, Claude, Gemini, Cohere, Mistral or Hugging Face.
• Experience with supervised fine-tuning (SFT), prompt tuning or instruction tuning using proprietary datasets.
• Strong understanding of LLM fine-tuning approaches, including SFT and RLHF/RLAIF.
• Excellent Python development skills.
• Experience with frameworks and tools such as LangChain, Hugging Face Transformers, Pandas, DVC or Weights & Biases.
• Knowledge of model evaluation techniques, including BLEU, ROUGE and custom evaluation frameworks.
• Exposure to speech technologies, including Whisper, ElevenLabs, Bark or similar platforms.
• Strong communication skills and the ability to collaborate with technical and non-technical stakeholders.
• A proactive, experimental mindset and the confidence to operate in an evolving technical environment.

Responsibilities

• LLM Fine-Tuning: Fine-tune large language models for tone, style and domain-specific applications.
• Dataset Engineering: Design, curate and manage high-quality datasets for fine-tuning, including annotation, versioning and data preparation workflows.
• RAG Development: Build, optimise and evaluate retrieval-augmented generation pipelines using structured and unstructured data.
• Voice & Audio AI: Prototype and test text-to-speech (TTS) and speech-to-text (STT) pipelines using technologies such as ElevenLabs, OpenAI TTS and Whisper.
• AI Prototyping: Collaborate with engineering, infrastructure, frontend and design teams to develop innovative AI-powered tools and applications.
• Model Evaluation: Develop and own evaluation frameworks using BLEU, ROUGE, custom metrics and human-in-the-loop feedback.
• Product Innovation: Support experimentation with real-time generation, summarisation, personalisation and intelligent content delivery.
• Cross-Functional Collaboration: Work closely with product teams, subject matter experts and business stakeholders to define quality standards and deliver meaningful AI solutions.

Skills

LLM/NLP expertise

Python development

Communication skills

Proactive, experimental mindset

Stakeholder collaboration

Tools

LangChain

Hugging Face Transformers

Pandas

DVC

Weights & Biases

Job description

167Solutions is partnering with a leading global organisation to recruit an experienced AI / LLM Engineer for an exciting new Generative AI Innovation Lab. You’ll join a small, highly skilled team building, fine-tuning and deploying LLM-powered systems focused on tone, retrieval-augmented generation and multimodal AI, including audio and voice technologies.

As an early engineer, you’ll shape direction with product and design leadership and own end-to-end delivery from prototype to production for