Founding Engineer | Head of Engineering

Dex; Greater London; On-site; GBP 120,000 - 180,000; Full time

Job summary

Dex, in partnership with a pioneering fintech, is building a new core banking platform from first principles in London. The role focuses on designing secure, scalable financial infrastructure and owning the architecture end to end.

You will translate ambitious product concepts into production-ready systems, establish engineering culture, and recruit the founding team as the company scales, with in-person collaboration in London.

Qualifications

• 5-12 years of engineering experience in backend systems, infrastructure and production architecture.
• Experience building complex, regulated financial infrastructure (core banking, ledger, payments).
• Founding engineer/early hire or senior scale-up experience in fintech or infrastructure.

Responsibilities

• Architect, build, and own the core banking platform from first principles.
• Design and implement highly secure, scalable, and regulated financial infrastructure.
• Drive all technical decisions across architecture, infrastructure, security, and product engineering.
• Translate product concepts into production-ready systems with data integrity and reliability.
• Establish the engineering culture and recruit the foundational team as the company scales.

Skills

Backend systems

Distributed systems

Cloud infrastructure

Data integrity

Reliability

Security

Tools

APIs

Distributed systems

Cloud infrastructure

Data integrity

Reliability

Security

Job description

This role is with one of Dex's trusted partner companies. We work closely with their teams to truly understand their culture, goals, and what they're looking for, so we can match you with the right opportunity and give you context about the role before you commit to a process.

The role

This team is building a new financial institution from first principles, purpose-built for the companies driving Europe's defence, security, and resilience buildout. A trillion-euro market is opening up, and the startups underpinning that shift are poorly served by traditional banks. This company exists to bank and finance them, backed by a highly selective accelerator.

The work

• Architect, build, and own the entire core banking platform from first principles.
• Design and implement highly secure, scalable, and regulated financial infrastructure.
• Drive all technical decisions across architecture, infrastructure, security, and product engineering.
• Translate ambitious product concepts into production-ready systems, ensuring data integrity and reliability.
• Establish the engineering culture and recruit the foundational team as the company scales.

What You Bring

• 5-12 years of engineering experience with deep expertise in backend systems, infrastructure, and production architecture.
• Proven track record building complex, highly regulated financial infrastructure (e.g., core banking, ledger systems, payments).
• Experience as a founding engineer, early hire, or senior engineer scaling a high-growth fintech or infrastructure company.
• Expertise in APIs, distributed systems, cloud infrastructure, data integrity, reliability, and security.
• London-based or willing to relocate, committed to in-person collaboration.

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