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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.

About this role

Role overview

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.

About the company

Briefcase

Briefcase

Software Development2-10 employees

AI-native financial automation startup building an autonomous autopilot for accounting

What you'll do

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 you are

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

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.

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