Senior Fintech Architect — AWS, Scalable Microservices

kast.xyz; Greater London; On-site; GBP 120,000 - 180,000; Full time

Job summary

KAST is seeking a seasoned Principal Architect to own and drive our technical strategy for a high-throughput fintech platform. You will lead the architecture for a resilient, scalable microservices ecosystem on AWS, ensuring security and performance as we scale globally.

Partner with engineering, product and security leaders to set standards for deployment, governance, and data integrity. This role combines hands-on architecture with mentorship of senior engineers and strategic influence across

Qualifications

• 10+ years of software engineering with large-scale fintech experience.
• Expert in microservices and distributed systems.
• Extensive AWS cloud design and operations experience.
• Strong understanding of financial data integrity and transaction patterns.
• Ability to influence technical direction across multiple teams.
• Security-by-design mindset for regulated environments.
• Growth mindset balancing delivery with architectural debt management.

Responsibilities

• Own the Architectural Vision: Define and drive the long-term technical architecture for KAST, ensuring platform evolves for high-throughput needs.
• Design for Scale & Reliability: Lead the design and review of distributed systems for fault tolerance and high availability on AWS.
• Optimize Transactional Flows: Architect critical paths including payment processing and ledger systems with sub-millisecond performance.
• Establish Engineering Standards: Define architecture principles, coding standards, and deployment patterns (CI/CD, IaC).
• Cloud-Native Strategy: Lead AWS strategy, optimize resource utilization, latency and cost.
• Drive Security & Compliance: Integrate security-by-design principles to meet PCI-DSS, SOC2.
• Influence & Mentor: Mentor senior engineers, lead architecture review boards, guide major decisions.

Skills

Fintech leadership

Distributed systems

AWS

Data integrity

Strategic influence

Security & compliance

Growth mindset

Tools

AWS

Job description

KAST is seeking a seasoned Principal Architect to own and drive our technical strategy for a high-throughput fintech platform. You will lead the architecture for a resilient, scalable microservices ecosystem on AWS, ensuring security and performance as we scale globally.

Partner with engineering, product and security leaders to set standards for deployment, governance, and data integrity. This role combines hands-on architecture with mentorship of senior engineers and strategic influence across