Founding Product Engineer

ZipRecruiter; City Of London; On-site; GBP 80,000 - 100,000; Full time

Job summary

A fintech startup is seeking a founding backend engineer to design, build, and launch its core platform in London. This high-impact role involves working directly with founders, using C#/.NET 8, and leveraging AI for development. Candidates should possess strong backend API skills and a willingness to embrace challenges, with opportunities for equity in the company.

Benefits

Generous equity options

In-person collaboration

High-impact role

Qualifications

• Strong grasp of enterprise architecture patterns (DDD, CQRS, microservices).
• Experience in payments and fintech is a plus.
• Comfort with cloud infrastructure, preferably AWS.

Responsibilities

• Design, build, and launch our core platform.
• Write code daily and influence key architectural decisions.
• Build a modern backend from scratch.

Skills

C#

AI usage in development

Backend API development

DevOps

Tools

AWS

C#/.NET 8

PostgreSQL

React

Job description

About Us

We are an early-stage fintech startup (not rebuilding but) re-wiring the global payments infrastructure. Today, sending money across borders is slow, expensive, and fragmented. We\'re here to fix that—making instant cross-border payments a reality. We’re an early-stage fintech startup, backed by industry insiders, with deep experience in the financial ecosystem. We’re building from zero—no tech debt, no legacy systems. Just a clean slate, strong vision, and higher standards. Now we’re looking for a founding backend engineer to join us at the ground level and help bring this platform to life.

The Role

• You’ll work directly with the founders to design, build, and launch our core platform
• This is a hands-on, high-impact role: you\'ll write code daily, influence key architectural decisions, and ship fast using modern tools and AI.
• Build a modern backend from scratch in C#/.NET 8 with a clean, event-driven architecture
• Help architect a scalable system using CQRS, Event Sourcing, DDD, microservices
• Own key components in AWS: Lambda, SQS, SNS, DynamoDB, PostgreSQL, API Gateway
• Work in a test-first, high-trust environment with real autonomy

What we\'re after

• You work incredibly hard, have high agency and take pride in what you do
• You (love using) use AI to design, code, debug, and ship (way) faster (if you think AI is a nuisance, this is not for you)
• You are comfortable building backend APIs, front-end web apps, DevOps and systems integrations. Whatever comes your way.
• C# is a must. React nice to have. The rest you can learn

Desirable

• You like the idea of becoming a start-up Founder one day
• Comfort with cloud- infrastructure (preferably AWS)
• Background in payments & fintech
• Strong grasp of enterprise architecture patterns (DDD, CQRS, microservices)

What we\'re after:

• Opportunity to join at the early stage and build the world\'s first instant and open payments network
• You\’ll work directly with the founder to design, build, and launch our core platform
• You will be working at the bleeding edge of AI development within an enterprise environment
• Hands-on, high-impact role: you\'ll write code daily, influence key architectural decisions, and ship fast using modern tools and AI

Why Join Us?

• Build from 0 to 1: You\’ll shape the architecture, team, and product from day one
• Real ownership: You won\'t be a cog—you\’ll be a core part of the company\'s foundation
• Mission-driven: Help reinvent a critical piece of global financial infrastructure
• Equity upside: Generous options in what we believe can be a fintech company
• Work with intensity and purpose, in-person with a small team of true builders in London

Why you shouldn\'t join

• Expectations are incredibly high
• You’re looking for a comfy job with a 40 hour a week commitment with predictable hours and minimal pressure
• You don\'t see the value in using AI to enhance engineering teams

Logistics

• Location: In-person in London 5 days a week with some flexibility
• Compensation: Competitive salary + high-equity package

To apply please send 1) your CV, 2) a quick note on why you want to join and 3) how you are using AI today to hello [at] 3degrees [dot] co

No visa sponsorship of any kind at this point.