Lead Platform Engineer

Company: La Fosse
Apply for the Lead Platform Engineer
Location: London
Job Description:

Lead Software Engineer (backend and AI focusses) – Up to £160k – London

We’re partnering with a venture-backed AI startup building an AI-native platform that combines automation, voice AI, and agentic workflows to solve complex real-world operational problems. Engineering sits at the heart of the business, with AI embedded into both the product and the way the team builds software.

As a Lead Software Engineer, you’ll work directly with the Head of Engineering in a highly impactful, hands-on role. This is a fast-moving startup environment where adaptability is key. The focus is primarily Node.js, with Python used across AI initiatives, automation, and LLM-powered features. Open to moving into more senior postions as the team grows!

What you’ll be doing

  • Building and scaling backend services using Node.js and TypeScript.
  • Developing AI-powered features, agentic workflows, and automation tools.
  • Working closely with engineering leadership on technical strategy and architecture.
  • Using Python to support AI, data, and machine learning initiatives.
  • Taking products from idea through to production in a high-ownership environment.
  • Helping shape engineering best practices in an AI-first business.
  • Managing a small engineering team.

What we’re looking for

  • Strong commercial experience with Node.js, TypeScript, NestJS, REST APIs and distributed systems.
  • Experience building products in startups, scale-ups or high-growth technology businesses.
  • Hands-on experience with Python and an interest in Generative AI, LLMs, AI Agents, Agentic Workflows, Retrieval-Augmented Generation (RAG), Prompt Engineering and AI Automation.
  • Experience integrating with models such as OpenAI, Anthropic Claude, Gemini or open-source LLMs.
  • Strong understanding of system design, microservices, event-driven architecture and cloud-native development.
  • Experience working with PostgreSQL, MongoDB, Vector Databases (Qdrant, Pinecone, Weaviate or similar).
  • Comfortable working in ambiguous environments where priorities evolve quickly.
  • Product-minded engineer who wants to own outcomes, not just tickets.

Nice to have

  • Experience with AI products, agents, or LLM integrations.
  • Knowledge of cloud infrastructure, microservices, and event-driven systems.
  • Exposure to NestJS, Next.js, or modern frontend technologies.
  • Previous experience in a venture-backed startup.

Lead Software Engineer (backend and AI focusses) – Up to £160k – London

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Posted: September 14th, 2026