Senior AI Engineer

Job Title: Senior AI Engineer

Company: 167 Solutions

Location: Hybrid (UK ONLY)

Salary: £100,000 – £140,000 per annum

Contract Type: Permanent

Experience Level: Minimum 5 years' experience

Start Date: ASAP

About 167Solutions

167Solutions is a specialist technology recruitment partner, connecting talented professionals with organisations delivering innovative and business-critical technology initiatives.

We focus on understanding both the technical requirements of a role and the ambitions of the people we represent, helping to create meaningful, long-term career opportunities.

Our team will support you throughout the recruitment journey, offering clear communication, insight into the opportunity and guidance at every stage.

The Opportunity

167Solutions is partnering with a leading global organisation to recruit an experienced AI / LLM Engineer for an exciting new Generative AI Innovation Lab.

This is a unique opportunity to join a small, highly skilled team at the forefront of applied artificial intelligence, exploring how generative AI can transform digital products, content experiences and customer engagement.

You'll play a key role in building, fine-tuning and deploying LLM-powered systems, with a particular focus on tone and style alignment, retrieval-augmented generation (RAG), and multimodal AI, including audio and voice technologies.

This is a genuine zero-to-one engineering opportunity, where you'll have the freedom to experiment, innovate and take ideas from early prototypes through to working products used by a global audience.

As one of the first engineers joining this dedicated innovation team, you'll work closely with technical, design and product leadership to shape the direction of cutting-edge AI initiatives.

If you enjoy solving complex technical challenges, moving quickly and building innovative experiences across text, voice and visual interfaces, this could be an excellent next step.

What you'll be doing

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.

What we're looking for

We're looking for an engineer who combines strong technical expertise with a genuine passion for exploring what's possible with Generative AI.

Essential Skills & Experience

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 the principles of 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.

Desirable Experience

Strong candidates may also bring experience in

Fine-tuning LLMs for specific personas, communication styles or domain-specific use cases.

LangSmith or similar LLM observability and testing platforms.

Voice synthesis, voice cloning or emotion-conditioned audio generation.

AI applications within digital media, content platforms or other customer-facing environments.

Multimodal AI solutions combining text, image and audio.

Contributions to open-source AI/ML projects.

Responsible AI, model governance and the ethical considerations surrounding AI-generated content.

What makes this role particularly exciting

Early-stage influence: Join as one of the founding engineers and help shape the technical direction.

Genuine innovation: Work on exploratory, high-impact AI projects rather than simply maintaining existing systems.

Modern AI stack: Gain hands-on exposure to the latest LLMs, fine-tuning approaches, RAG architectures and multimodal technologies.

End-to-end ownership: Take ideas from concept and experimentation through to real-world implementation.

Collaborative environment: Work directly with senior technical, product and design specialists.

Global impact: Build solutions with the potential to reach and influence a substantial international audience.

Want to find out more

If you're an experienced AI / LLM Engineer looking to work at the cutting edge of Generative AI, we'd love to hear from you.

Apply directly through 167Solutions for a confidential discussion about the role, the team and the opportunity.