Staff Product Engineer (AI -Series A)

What's on offer

• Location: Chancery Lane. Central London
• Salary - £130,000- £160,000 per annum
• Reporting line - Matt Co-founder and CTO
• Benefits - Equity, Private Medical

What are we building?

Great people are working on overdrive to do a great job, but are held back because their inbox is failing them.

We're building an AI Productivity tool that eliminates the admin burden for people who work client facing roles. Think real estate, consultants, recruiters - people who spend hours on emails, scheduling, and follow ups. Fyxer AI simplifies these tasks by organizing your inbox, drafting replies in your own voice, and taking crisp meeting notes.

The best part? Unlike a lot of other AI tools, ours actually gets used.

We've built the product so it requires little set up & nothing extra for users to learn. It works directly inside Outlook, Gmail, & Zoom.

How has it been going?

Since our launch in May 2024, we've grown from $0 to $8 million in revenue, serving thousands of paying users. In February 2025, we raised a $10 million Series A to accelerate our path to $50 million in revenue-backed by top-tier investors including Marc Benioff (CEO of Salesforce) and 20VC.

We spent Q4 2024 in San Francisco at HF0, the best AI startup accelerator in the world, learning from experts like the CEO of Instacart, Head of Applied Research at OpenAI and the Co-founder of Snowflake. We're now at the stage of hypergrowth and are looking for the best of the best.

What do we value?

Autonomy, agency, and ownership.

Each of our Product Engineers owns one of Fyxer AI's products. They own both the product strategy (we have no product managers and have no plans for that to change) and the execution of that strategy. They choose when to bring in qualitative data (customer interviews, surveys etc) and quantitative, supported by our data engineering department.

We believe small, passionate teams outperform big, unfocused ones every time. That's why we're highly selective about who joins us. We're looking for people who bring intensity, creativity, and genuine care to their work.

You'll take on meaningful responsibilities from day one, with opportunities to grow faster than at most companies. We trust our team with real ownership and autonomy because that's how the best work happens.

What will I do?

In short, own one of Fyxer AI'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 our ideal hire look like?

• You've worked at an early stage tech company as a staff or lead engineer (

• 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
• High interest in AI and the problem we're using it to solve
• Urgency and intensity in your work

Our tech stack

Broadly, we use a fairly 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 our production database
• Firebase Auth as our auth system
• Backend deployed on Firebase Functions, and making use of PubSub 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 our data warehouse, with Metabase for data visualization. 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

The application process

1. Submit your CV (no need for a cover letter)
2. An initial call with someone from the Fyxer AI team to review your experience and motivation for joining (20-30mins)
3. Product case study, remote (45 minutes)
4. Live coding, remote (60 minutes)
5. Meet team in office (60 minutes)