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Lead Product Engineer

Job in City Of London, Central London, Greater London, England, UK
Listing for: Fyxer AI
Full Time position
Listed on 2025-11-24
Job specializations:
  • IT/Tech
    AI Engineer, Machine Learning/ ML Engineer, Data Analyst
Job Description & How to Apply Below
Location: City Of London

Hiring Overview

3 days ago Be among the first 25 applicants

We hire founders "This is the most exciting time in history to build." Sam Altman

Should I start a company? Should I keep going with my startup? What problem should I solve? "Starting by thinking up a problem is risky because you may invent a problem that doesn’t truly exist. If you can’t answer [‘who wants this right now?’], then the idea is probably bad." Paul Graham

We believe the best thing you can do right now is join a breakout AI team, face real problems, work with potential co‑founders, and make a lot of money.

What We’re Building

We’re solving the biggest problem in modern work:
email
. And we’re doing it at the best possible time in history to solve it. We think the best user experiences come from focus. For us, that means AI‑generated email drafts
. We’re laser‑focused on making them better over time, using context from your meetings, inbox, and messages, because that’s what matters most to our users.

Unlike other startups, we’re a pure‑play applied AI company
, not a SaaS tool with AI bolted on. We use the best techniques, including fine‑tuned open‑source models, tool use, and retrieval‑augmented generation. As a result, users send 53% of the drafts we generate.

Your Background
  • 5+ years of experience building and shipping production software, with deep expertise in Python or Type Script and a track record of owning systems end‑to‑end.
  • Hands‑on experience with modern AI/ML tooling (LLMs, fine‑tuning, RAG, embeddings, distributed training, inference optimisation, etc.) and proven ability to work directly with models in production.
  • Strong product intuition and user‑centric mindset, able to translate ambiguous problems into simple, high‑impact product decisions without product managers.
  • Startup‑ready mindset: comfortable operating with extreme ownership, rapid iteration, and high autonomy within a small, elite technical team.
How’s it going?

This year, we’ve grown from $1M to $25M ARR
, with a technical team of just 12 (up from
2). We’re forecasting $100M ARR by the end of 2025. We have product‑market fit, and we take none of it for granted. We’re relentlessly focused. There will be a $10B+ company in this space. It will be us if we stay focused. Ranked 7th in Andreessen Horowitz’s list of top AI apps
, based on real startup spend data. The other nine in the top 10 are valued at $10B+.

Autonomy, Agency, Ownership

Team members own both product strategy (we have no product managers and no plans to add them) and the execution of that strategy. They decide when to bring in qualitative insights (interviews, surveys, etc.) or quantitative data, supported by our data engineering team.

Our Technical Staff Focus On
  • Building an incredible product
  • Helping users find value and share
  • Training cutting‑edge models
  • Developing scalable infrastructure
We’re Deliberate About Hiring

A small team of exceptional people, working hard on a problem they care about, will always beat a larger, less focused team. That intensity means this isn’t a normal role, but it also means you’ll move faster than anywhere else.

Examples
  • Serafin joined 6 months ago and built our entire product notetaker, competing with whole companies, including research, model training, and product development.
  • Joey joined 7 months ago and built our human data platform for model training and evals.
  • Josh joined 14 months ago and now leads infrastructure, having built core products like scheduling along the way.
What We Promise

Most fast‑growing startups fall into traps: over hiring, losing focus, acting like big companies. We believe small, exceptional, high‑performing teams are the future.

  • No bureaucracy
  • No processes that slow decisions
  • No constant distractions, we have company‑wide focus time with no meetings until 3pm

A humble but extremely ambitious environment. A group of people giving unreasonable effort to the right things.

What We Pay

We offer the highest cash and equity in London, up to £500k package!

Seniority level

Mid‑Senior level

Employment type

Full‑time

Job function

Engineering and Information Technology

Industries:
Software Development

Referrals increase your chances of interviewing at Fyxer AI by 2x

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