Staff Product Engineer

ZipRecruiter; City Of London; Hybrid; GBP 150,000 - 250,000; Full time

Job summary

A leading AI startup in London is seeking a Staff Product Engineer to own product development and drive the product strategy. The role requires expertise in TypeScript and serverless architecture, with responsibilities including mentoring engineers and shaping product direction. The company provides a competitive salary of up to £200K and unique opportunities for growth in a collaborative environment.

Benefits

Up to £200K base salary + equity

Private medical insurance

Private dental insurance

25 days annual leave

Visa sponsorship available

Qualifications

• Expert level understanding of TypeScript and serverless architecture required.
• Experience in early stage tech companies or as a founder desired.
• Capability to develop features autonomously based on customer feedback.

Responsibilities

• Own one of Fyxer's most important products.
• Define product metrics and understand value through use and customer feedback.
• Mentor and develop other product engineers.

Skills

TypeScript

Serverless Architecture

Fullstack Development

SQL

AI Interest

Tools

React

Firebase

Posthog

BigQuery

Job description

Overview

We are thrilled to be partnering exclusively with Fyxer AI - the fastest growing AI start-up in the UK - to recruit a world-class Staff Product Engineer for their London team.

What Are They Building?

Great people are working on overdrive to do a great job but are held back because their inbox is failing them. Fyxer AI is building an AI productivity tool that eliminates admin for client-facing professionals: consultants, recruiters, real estate agents anyone drowning in emails, scheduling, and follow-ups. Fyxer AI drafts emails in your voice, takes crisp meeting notes, and auto-manages your inbox.

How’s It Going?

Since launching in May 2024, they've grown from $0 to $15+ ARR with thousands of paying users. In Feb 2025, they raised a $10M Series A backed by top-tier investors including Marc Benioff (Salesforce) and 20VC.

They spent Q4 2024 at HF0 in San Francisco, the top AI startup accelerator, learning from legends like the CEO of Instacart and the Head of Applied Research at OpenAI.

They are now entering hypergrowth and building the engineering team that will scale them to $50M+ in revenue.

What They Value

Small teams. Big ownership. High talent density.

They don’t hire for headcount. They hire people who ship, who care, and who think from first principles.

They only hire product engineers. What that means is instead of just being given tickets to implement, you’ll be owning a whole product: shaping the roadmap by thinking from first principles, looking at usage data and speaking to customers, then architecting and implementing your ideas.

What Will You Be Doing?

In short, you will own one of Fyxer's most important products:

• Decide on metrics for your product, and gain an intuitive understanding of its value by using it yourself and speaking to customers.


• Use quantitative data, customer insight, and product sense to build a strategy for your product area, and prioritise initiatives within that strategy


• Execute your strategy by coding up your ideas


• Manage and improve reliability in your product area, by monitoring logs, analysing support tickets and fixing bugs

A key area for responsibility will be mentoring and developing other product engineers, setting the product direction for a large area of the business, and setting the direction for the tooling the team uses internally to be productive.

What Does The Ideal Hire Look Like?

• You’ve worked at an early stage tech company (<100 people), or been a founder


• You have an expert level understanding of TypeScript and serverless architecture. If you don’t have these, you shouldn’t apply


• You want to get involved in product work, rather than just being handed tickets. You’ll be expected to come up with features autonomously, by reading customer feedback and analysing usage data


• You can function as a fullstack engineer, working on client and server side code, and answering data questions using SQL


• You have a high interest in AI and the problem they’re using it to solve


• You have urgency and intensity in your work

What Does The Company Value?

Autonomy, agency and ownership. They believe small, passionate teams outperform big, unfocused ones every time. That’s why they’re highly selective about who joins them. They are looking for people who bring intensity, creativity and genuine care to their work. They trust their team with real ownership and autonomy because that’s how the best work happens. They’re building a world-class team of incredible people. In order to foster a productive and rapidly scaling culture, the team comes together 4 days per week in the Chancery Lane office in London.

Tech Stack

Fyxer AI uses a typical serverless TypeScript stack. It\'s not a requirement to have worked with every tool in this stack, but the more the better!

• TypeScript for all production code


• Firestore as the production database


• Firebase Auth as the auth system


• Backend deployed on Firebase Functions, and making use of Pub/Sub and Cloud Storage


• React frontend, using ShadCN for components, TailwindCSS for styling, React Query for state management


• Posthog for frontend analytics (events, sessions, feature flags, experiments)


• BigQuery as the data warehouse, with Metabase for data visualisation. Production data and Posthog events both stream into it so data is in one place


• Sentry and Google Cloud Logging for monitoring


• Github Actions for CI/CD

What\u2019s In It For You?

• Up to £200K base salary + equity


• Private medical insurance


• Private dental insurance


• Pension


• 25 days annual leave


• Visa sponsorship if required for exceptional candidates


• The opportunity to build the UK’s fastest growing AI company with a world-class team

***This role is based in Chancery Lane, London 4 days-per week. We are looking for candidates who value in-person collaboration.***