Fintech Principal Architect: Scale, Security & Cloud

KAST; Greater London; Hybrid; GBP 140,000 - 190,000; Full time

Job summary

KAST is seeking a seasoned Principal Architect to own and drive our technical strategy as we scale a global fintech platform. You will be the primary authority for system design, ensuring high‑throughput transaction engines and a complex microservices ecosystem remain resilient, performant, and secure under heavy load.

You’ll partner with Engineering, Product and Security to set standards for building and deploying transactional infrastructure on AWS.

Qualifications

• 10+ years of software engineering experience with fintech platforms.
• Led large-scale payment or ledger systems or high-volume financial infrastructure.
• Expertise in microservices and event-driven design for scalable systems.
• Extensive AWS/cloud-native architecture experience.
• Knowledge of security and compliance standards in regulated environments.

Responsibilities

• Own the architectural vision for high-throughput platforms.
• Design for scale, reliability, and fault tolerance on AWS.
• Optimize transactional flows with sub-millisecond performance.
• Define coding standards and deployment patterns for autonomous teams.
• Lead AWS strategy to improve latency and cost efficiency.
• Mentor engineers and guide major technical decisions.

Skills

Fintech leadership

Distributed systems

Cloud - AWS

Security & compliance

Architectural leadership

Job description

KAST is seeking a seasoned Principal Architect to own and drive our technical strategy as we scale a global fintech platform. You will be the primary authority for system design, ensuring high‑throughput transaction engines and a complex microservices ecosystem remain resilient, performant, and secure under heavy load.

You’ll partner with Engineering, Product and Security to set standards for building and deploying transactional infrastructure on AWS.