At a Glance
- Tasks: Own product delivery from spec to production, focusing on backend systems and LLM integration.
- Company: Exciting seed-stage AI company in London with a strong backing.
- Benefits: Above market salary, equity, private healthcare, gym membership, and wellness perks.
- Other info: Dynamic environment with fast iteration and excellent career growth opportunities.
- Why this job: Join a lean team to shape innovative products and make a real impact.
- Qualifications: Strong Python backend skills, experience with LLMs, and cross-functional collaboration.
The predicted salary is between 80000 - 100000 £ per year.
Partnering with a well-backed seed-stage AI company in London, Foundation Partners are hiring for several founding Senior Engineers to a technically strong & lean Eng team, shape 'how' in addition to 'what' is built and help the company prepare for the next iteration of their scaling journey.
The Role
This is a full-stack product role with a backend-heavy centre of gravity. You'll own complete product slices end-to-end and you'll ship these without needing to be guided. You're not a specialist who hands off at the API boundary. You think in user outcomes and delivery units, and you're reliable: your code handles edge cases, your APIs have clean contracts, and the work you ship stays shipped.
What You'll Do
- Own product delivery — take features from spec to production, backend-first but covering frontend and integration where needed
- Build and maintain backend systems — product APIs, data pipelines, and core infrastructure on our Python/FastAPI/Postgres stack
- Build with LLMs and agents — ship product features with significant LLM integration; contribute to the voice agent backend and information extraction systems
- Work across the stack — ship workable React/TypeScript frontend for product features; not a frontend specialist, but comfortable and pragmatic
- Collaborate with product and design — translate ambiguous requirements into concrete shipped work; be the engineer who unblocks, not the one who waits
- Maintain quality at speed — handle data integrity, error paths, API evolution, and operational concerns as a default, not an afterthought
What We're Looking For
- Independent delivery — You can own and ship end-to-end product slices with minimal supervision; your track record shows features that shipped, stuck, and scaled
- Product trade-off judgment — you balance speed, quality, and user impact under ambiguity; you push back when something is underspecified and make pragmatic calls when it needs to ship
- Reliability and API discipline — you handle data integrity, error paths, idempotence, and API versioning as standard practice; production reliability is your default, not a later concern
- Cross-functional pragmatism — you work effectively with product and design, can unblock yourself across the stack, and ship workable frontend when that's what's needed
Strong technical depth in:
- Python backend (FastAPI or equivalent, async patterns, Postgres, Redis)
- LLM integration — building products where AI is in the critical path, not bolted on
- API design and data modelling
- JavaScript/TypeScript — comfortable enough to ship frontend features and review frontend PRs
Nice to Have
- Experience with voice agents or real-time audio pipelines
- Familiarity with evals, guardrails, or agent observability
- Familiarity with GCP / cloud infrastructure
- Experience in recruiting tech, marketplaces, or matching systems
The Stack
A modern Python stack: FastAPI, Postgres, Redis, Docker, Pydantic AI, running on GCP. Frontend in React/TypeScript. We iterate fast and keep the codebase clean.
We'll offer you:
- Above market salary
- Meaningful equity
- Full private healthcare & dental
- Fertility benefits & enhanced parental support
- Gym membership & wellness benefits
- LOTS of Claude tokens
- Regular socials, offsites and an annual trip
- MacBook Pro + team kit
- "Whatever you need" approach to tools and support
Founding Senior Product Engineer in London employer: Foundation Partners Group
As a founding Senior Product Engineer at this innovative AI company in London, you'll be part of a dynamic and technically adept team that values independence and ownership in product delivery. The company fosters a collaborative work culture with a strong emphasis on employee growth, offering above-market salaries, meaningful equity, and comprehensive benefits including private healthcare, wellness perks, and regular team socials, making it an exceptional place for those seeking to make a significant impact in the tech landscape.
StudySmarter Expert Advice🤫
We think this is how you could land Founding Senior Product Engineer in London
✨Tip Number 1
Network like a pro! Reach out to people in the industry, attend meetups, and connect with potential colleagues on LinkedIn. You never know who might have the inside scoop on job openings or can refer you directly.
✨Tip Number 2
Show off your skills! Create a portfolio showcasing your projects, especially those involving Python, FastAPI, or LLMs. This gives you a chance to demonstrate your end-to-end delivery capabilities and technical depth.
✨Tip Number 3
Prepare for interviews by practising common technical questions and coding challenges. Focus on demonstrating your reliability and ability to handle edge cases, as these are key traits for the role.
✨Tip Number 4
Apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, it shows you're genuinely interested in joining our team and contributing to our exciting journey.
We think you need these skills to ace Founding Senior Product Engineer in London
Some tips for your application 🫡
Show Your Independence:We want to see that you can own and ship product slices with minimal supervision. Highlight your past experiences where you've taken features from spec to production, showcasing your ability to deliver reliably.
Balance Speed and Quality:In your application, demonstrate how you make pragmatic decisions under ambiguity. Share examples of when you've pushed back on underspecified requirements and how you balanced speed with user impact.
Highlight Your Technical Depth:Make sure to detail your experience with our tech stack, especially Python, FastAPI, and Postgres. If you've worked with LLMs or have experience in API design, let us know – we love seeing that!
Collaborate Effectively:We value cross-functional teamwork, so mention any experiences where you've collaborated with product and design teams. Show us how you've translated ambiguous requirements into concrete work that shipped successfully.
How to prepare for a job interview at Foundation Partners Group
✨Know Your Stack Inside Out
Make sure you’re well-versed in the technologies mentioned in the job description, especially Python, FastAPI, and Postgres. Be ready to discuss your experience with these tools and how you've used them to deliver end-to-end product features.
✨Showcase Your Problem-Solving Skills
Prepare examples of how you've tackled ambiguous requirements in the past. Highlight situations where you had to make trade-offs between speed and quality, and how you ensured reliability in your code. This will demonstrate your ability to think critically and pragmatically.
✨Demonstrate Cross-Functional Collaboration
Be ready to talk about your experiences working with product and design teams. Share specific instances where you translated vague ideas into concrete deliverables, and how you’ve unblocked yourself or others in the process. This shows you’re a team player who can bridge gaps.
✨Prepare for Technical Challenges
Expect to face technical questions or coding challenges during the interview. Brush up on API design, data modelling, and LLM integration. Practising coding problems related to these areas will help you feel more confident and ready to impress.
