Founding Engineer in London

We are hiring Founding Engineers in London for three early-stage AI companies. All London-based, all building in production, and at the moment where the right technical hire changes everything. All three companies are past prototype, have paying customers or live products, and need someone who can own the technical direction, not just execute against a roadmap.

THE DOMAINS:

• An AI coaching platform for endurance athletes, with a live consumer app and a multi-agent system that adapts in real time to how people train, recover and live.
• A women's healthtech startup reimagining postnatal care, building clinical-grade, data-compliant infrastructure at the intersection of AI and regulated healthcare.
• An agentic AI platform automating freight forwarding workflows for an industry that moves $210BN and still runs on email and spreadsheets.

THE ROLE:

Founding Engineers are builders. You will work directly with founders, own technical decisions, and be accountable for what ships. Depending on the company, that means inheriting a well-structured production codebase and taking full ownership, or building core infrastructure from scratch. Either way, you’re not coming in to manage; you’re coming in to leave by doing. You’ll set architecture strategy, make build-versus-buy calls, raise engineering quality, and help shape the team as it grows. The best candidates will be energised by that scope, not daunted by it.

REQUIREMENTS:

• Strong Python in production, ideally including FastAPI or similar async frameworks.
• Proven experience building and deploying LLM-powered applications, not prototypes that never saw users.
• Solid understanding of data modelling and PostgreSQL; familiarity with vector databases is a plus.
• Comfortable across the full stack, backend-first but able to move into React/TypeScript and mobile when needed.
• Experience with CI/CD, Docker and cloud infrastructure (AWS or GCP), and the discipline to build robust systems that scale.
• AI and agent-specific skills.
• Experience designing and optimising multi-agent systems for reliability and production performance.
• Understanding of prompt engineering techniques including few-shot learning, chain-of-thought and RAG.
• Familiarity with LLM evaluation strategies and how to measure whether your system is actually working.
• Hands-on with AI orchestration frameworks: LangGraph, LangChain, DSPy or equivalent.
• Knowledge of model optimisation for production deployment (quantisation, distillation, fine-tuning approaches) is a strong plus for at least one of these roles.

Attributes:

• Strong technical judgement on speed, quality, debt and long-term maintainability.
• Ability to take ownership of an existing codebase, understand its trade-offs, and improve it without ego.
• Experience contributing to hiring decisions, shaping engineering culture, or building a team from scratch.
• Comfortable operating with autonomy in high-trust, early-stage environments where the brief changes and you have to figure it out.

The practicalities:

• All roles are London-based with in-office presence required (3+ days per week).
• Competitive 6-figure salaries plus meaningful early-stage equity.
• Not offering sponsorship - if you don’t have the right to work in the UK, don’t apply.

Interested? Reach out directly and tell us which domain caught your attention. Reach out to Kelly Gauthier (kelly@highersearch.co) or George Alexander (george@highersearch.co). We’ll share more detail on the specific opportunity and help you work out where you’re the best fit.

Unfortunately, we are not able to offer sponsorship to foreign candidates. If you are not able to live and work in London without sponsorship, please do not apply.