Engineer jobs in United Kingdom

Unlocking Tech is hiring an AI Full-Stack Engineer to help us build and scale our AI-powered agents and automation products.

You’ll work at the intersection of LLMs, backend engineering, and product, designing and shipping end-to-end solutions: from a voice or WhatsApp agent talking to patients or leads, to the backend services, RAG pipelines, and cloud infrastructure behind it.

Our stack powers automation for clinics, real estate, industry, and internal platforms, with use cases like:

• AI receptionists for clinics (voice + WhatsApp),
• lead qualification agents for sales teams,
• document/question answering copilots on top of PDFs, contracts, and emails,
• internal tools for our own omnichannel AI platform.

This is a hands‑on engineering role: you’ll both build and ship.

• Design, build, and maintain end-to-end AI features: from prompt / agent design all the way to API endpoints and (sometimes) basic UI integration.
• Implement and evolve LLM-powered agents (voice, chat, WhatsApp, web) using LLM APIs, tools, memory, RAG, and external system integrations.
• Build RAG/document intelligence pipelines on top of PDFs, DOCX, emails, and other unstructured data (parsing, chunking, embeddings, retrieval, evaluation).
• Develop and maintain backend services and APIs (REST/webhooks) in Node.js/TypeScript or Python that integrate with CRMs, telephony providers, and third‑party SaaS.
• Work with vector databases and relational databases to store embeddings, logs, sessions, and agent state.
• Deploy and operate services on Azure / other cloud providers using Docker and basic CI/CD.
• Implement monitoring, logging, and tracing for AI services (latency, token usage, errors, user feedback).
• Collaborate with frontend engineers and product to ship features quickly, gather feedback, and iterate.
• Document architecture, APIs, and technical decisions in a way the rest of the team can follow and extend.

• 5+ years of experience as a Software Engineer (backend or full-stack) shipping production systems.
• Strong skills in at least one of:
  • Node.js / TypeScript
  • Python
  • (.NET is a plus because of our legacy stack)
• Solid experience building REST APIs, integrating with external APIs, and working with webhooks.
• Hands‑on experience using LLM APIs (OpenAI, Anthropic, etc.) to build real features (chatbots, agents, copilots, document Q&A, etc.).
• Understanding of RAG patterns (chunking strategies, embeddings, retrieval, context window management).
• Experience with databases (PostgreSQL/MySQL) and at least one vector database or extension (Pinecone, pgvector, Qdrant, Weaviate, etc.).
• Comfortable working with Docker, Git, and basic CI/CD workflows.
• Familiarity with a major cloud provider (Azure is a plus).
• Ability to own features end-to-end, communicate clearly in English, and work in a small, fast‑moving team.

• Experience building AI agents with LangChain, LlamaIndex, Haystack or similar frameworks.
• Integrations with telephony / messaging providers (Twilio, VAPI, Zadarma, WhatsApp Business API, SMS gateways).
• Experience with n8n or other automation/orchestration platforms.
• Background in document AI: OCR, layout‑aware models, Azure Document Intelligence, Google Document AI, or similar.
• Some frontend experience (React or Angular) to help close the loop on small UI tasks when needed.
• Knowledge of LLM evaluation, guardrails, hallucination mitigation, and security/privacy concerns around AI.
• Exposure to Kubernetes, Terraform, or more advanced DevOps is a plus but not required at the start.
  

• Work on real, production‑grade AI agents and automation, not just prototypes or internal POCs.
• Be part of a fast‑moving team building our own AI-powered omnichannel platform (voice, WhatsApp, web).
• High autonomy and direct impact: your work will go live quickly and be used by real users and clients.
• Opportunity to experiment, learn, and ship across different verticals (healthcare, real estate, industry).
• Hybrid work model in Lisbon, close collaboration with the CEO and core engineering team.