Full Stack AI Engineer | Next.js, Python, LLMs | Fully remote, UK
£85,000 to £105,000 . Permanent.
London. Fully remote across the UK.
This is full stack in the literal sense. You will build the interface, backend and AI workflow, then stay with it when an agent stalls, a tool fails or the model returns something you did not plan for.
Our client is an early-stage AI product company building applications that get on with everyday tasks before you ask. A prototype exists, launch is ahead, and the company is funded without relying on an upcoming round.
You'll work in a small, distributed team with ML, backend and product engineers. You own a feature from the first screen to the last service call, and the AI sits inside the product, not behind a separate research hand-off.
The hard part is reliability. Multi-step workflows cross models, memory, tools and services. Streaming, partial results, latency and recovery have to be designed into the feature from the start. Adding them after launch doesn't work.
The job
Product. Build features across frontend, backend and AI integrations. The current stack includes Next.js, Python and Node.js, with SQL and NoSQL storage behind the product.
Agents. Design workflows that plan, use tools, retain context and recover across multiple steps. You'll integrate LLMs, memory and external tools into product behaviour that can be observed and improved.
Reliability. Build fallbacks and recovery around model and tool failures. You'll work on streaming and real-time AI interactions where latency, partial results and user feedback need deliberate handling.
Production. Ship the feature, watch how it behaves and iterate from real failure modes. Docker and Kubernetes are part of the stack, alongside OpenAI, Anthropic and open-source models.
What you'll bring
Essential:
- Full stack features you have taken from idea to production.
- Frontend and backend code you have both written yourself.
- LLM, RAG or agent-based applications you have shipped.
- API and system design used in a production product.
- Multi-step AI workflows involving tools, memory or orchestration.
- Production failures or latency problems you have traced across the whole stack.
- Work where you owned the feature after release, not only delivery.
- Existing right to work in the UK.
Useful:
Next.js, Python, Node.js, PyTorch, Kubernetes, Docker, SQL, NoSQL.
Who this suits
You are probably a Full Stack Engineer, Product Engineer or AI Engineer who likes owning the whole feature. You are comfortable moving from a user interaction to an API, an agent workflow and back again.
It won't suit you if you want the model to be somebody else's problem. Here the agent that stalls halfway through a task is your feature, and so is the fix.
Let's talk
Actively looking or just curious, we welcome applicants from every background and will support reasonable adjustments.
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Full Stack AI Engineer in London employer: Xist4 IT Limited.
As a Frontend Engineer at our innovative company, you'll be part of a dynamic team dedicated to creating AI-native productivity applications that redefine everyday tasks. We offer a fully remote work environment, fostering a collaborative culture where your contributions directly impact product development. With opportunities for professional growth and the chance to work on complex, engaging projects, we are committed to supporting your career while ensuring a rewarding and meaningful work experience.
