Join a high-performance team in London building a fleet of 15+ AI agents that automate complex financial workflows. As a founding engineer, you will ship code 20-30 times daily, architecting core features across React, TypeScript, and Temporal to redefine the industry’s system of record from the ground up.
Founding Product Engineer at Briefcase
Join an ambitious founding team in London building the future of finance with a fleet of autonomous AI agents. This isn't just another SaaS tool; it's a complete reimagining of accounting workflows where you'll ship 20-30 times a day and own the product end-to-end. If you are a high-agency engineer who thrives on urgency and wants to work with React, TypeScript, and the latest AI stacks alongside top-tier talent, this is your chance to build a category-defining company from the ground up.
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Location
London, United Kingdom
Compensation
Not Disclosed
Company
Briefcase
Role overview
Software Development2-10 employees
Briefcase is an AI accountant/bookkeeper: aiming to replace the work, not just augmenting it. Accounting is a $700B+ industry still run on manual processes and human judgement. We’re building the leading AI-native platform to replace it; a fleet of 35+ AI agents running in production today, automating what used to require entire teams. We are not building a tool, we are replacing knowledge workers. Backed by Earlybird, Entrepreneur First, Tiny, and prominent angels such as Charlie Songhurst.
What you will do
- Build and deploy industry-leading AI agents that handle end-to-end accounting workflows with humans-in-the-loop only where necessary.
- Engage directly with customers to identify pain points and rapidly iterate on product features from first principles.
- Drive technical decisions across the entire stack, refining architecture choices and experimenting with new tools to maintain high shipping velocity.
Who this is a fit for
- Proven track record of outperforming peers in high-growth environments with a deep passion for modern AI and product design.
- Expert-level proficiency in React, TypeScript, and GraphQL, with an interest in working with Temporal and AWS infrastructure.
- Strong bias for action and in-person collaboration, thriving in a fast-paced London-based office where the team ships dozens of times per day.
Why this role is remarkable
- Radical Agency: You will own the product roadmap end-to-end, moving from customer discovery to production deployment with total autonomy in a high-urgency environment.
- Frontier Tech: Work at the bleeding edge of AI agents, leveraging a modern stack including Langsmith, GraphQL, and bespoke data platforms to replace manual accounting.
- Founding Impact: As an early hire, you will directly shape the technical architecture, company culture, and product vision alongside a team of top-tier ambitious engineers.
How Jack & Jill work together
I get to know what you’re great at, then find roles you’d never find yourself.Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.
I recruit from Jack’s network and make the intro when I spot a great match.And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.
Jack gets to know what you're great at and what you want next, then searches 15 million jobs daily and helps you discover roles at companies like this.
Meet Jack
What happens next?
Jack’s an AI agent for job searching and career coaching. He works for you.
Jill is the AI recruiter working for the company. She recruits from Jack’s network.
If your profile’s a match and Briefcase wants to meet, Jill will make the intro. In the meantime, Jack will send you excellent alternatives.