Principal Engineer (Platform Architecture)

Cassini Systems; Greater London; Hybrid; GBP 120,000 - 170,000; Full time

Job summary

Cassini Systems is seeking a Principal Engineer (Platform Architecture) to lead the design and evolution of our analytics platform. You will shape technical direction, govern architecture across multiple teams, and mentor senior engineers.

You will collaborate with stakeholders to balance strategy, delivery, and long-term health of a scalable, secure platform while embedding AI-native workflows into the engineering lifecycle.

Qualifications

• University degree in a STEM subject from a reputable institution.
• Proven experience in a senior technical role such as Principal Engineer, Technical Architect, or equivalent position working with complex analytical system design.
• Track record of owning, shaping and governing architecture across multiple teams and large-scale platforms.
• Experience working with modern distributed and cloud-based systems.
• Familiarity with the tech stack or equivalent technologies.

Responsibilities

• Own and govern technical design and architecture across multiple development teams, defining standards and ensuring alignment with platform vision.
• Provide hands-on architectural leadership and guide complex design decisions.
• Partner with senior stakeholders to balance technical strategy and delivery needs.
• Champion the adoption of AI-native workflows within the engineering lifecycle.
• Mentor senior developers and tech leads to raise architectural standards.
• Ensure non-functional requirements (performance, scalability, security) are embedded from the outset.

Skills

Architectural judgment

Cross-team collaboration

Stakeholder communication

Problem solving

Ownership

Education

STEM degree

Tools

Python

React

Typescript

Redux

AWS

Docker

Linux

MySQL

RabbitMQ

Redis

GitLab

AI Agents

Job description

We are seeking a Principal Engineer (Platform Architecture) to help lead the design and evolution of our market-leading analytics platform, shaping technical direction while solving complex, real-world problems at scale.

About us

Founded in 2014, Cassini is the established, core utility provider of analytics and optimization tools for the derivatives industry. Trusted by hedge funds, asset managers, and banks worldwide, our platform delivers real-time, front-to-back insight into the full cost of derivatives trading.

Our award-winning platform empowers clients to reduce margin, optimize collateral, and enhance their liquidity risk framework, delivering real-time, front-to-back analytics on the full cost of derivatives trading.

What sets us apart?

• Recognised as 'Best Derivatives Tech Provider' and 'Analytics Leader’
• Global impactwith a rapidly expanding footprint
• Analytics provider to the largest asset managers in the world
• Enterprise-grade security(ISO 27001 & SOC-2)
• Seamless integrationwith OMS, EMS, and collateral systems

At Cassini, our client focus drives everything we do. You’ll work alongside experienced engineers, product specialists, and domain experts, tackling complex, real-world problems at the intersection of finance and technology. We offer challenging work, continuous learning, and the opportunity to have real impact on a platform used by leading financial institutions every day.

Role

In this role, you will ensure we build the right things, the right way.

You will report to the Head of Technology.

Core Responsibilities:

• Own and govern technical design and architecture across multiple development teams, defining standards, reviewing solution designs, and ensuring alignment with the broader platform vision
• Provide hands-on architectural leadership, guiding complex design decisions and supporting teams through critical implementations and production challenges
• Partner closely with senior stakeholders to balance technical strategy, delivery needs, and long-term platform health
• Champion the adoption of agentic and AI-native workflows, embedding them in the core engineering lifecycle
• Act as a primary technical point of contact for both internal and external stakeholders
• Identify and proactively address technical debt, risk, and cross-team dependencies, influencing roadmap planning and long-term platform health
• Mentor senior developers and tech leads, raising the overall architectural and engineering bar across the organisation
• Ensure non-functional requirements (performance, scalability, security, and resilience) are embedded from the outset

Tech Stack

We work with a modern stack designed for scale, reliability, and developer productivity. You don’t need to be an expert in every tool listed below, but you should have strong experience with most of them or equivalent technologies.

Core Languages & Frameworks

• Python (Flask, SQLAlchemy, NumPy, Pandas) for services and analytics
• React, Typescript, Redux for the front end

Cloud & Infrastructure

• AWS (ECS, Lambda, RDS, S3)
• Docker
• Linux

Data, Messaging & Caching

• MySQL
• RabbitMQ
• Redis

Tooling & DevOps

• GitLab for source control and CI/CD

AI & Automation

• AI Agents & Assistants used to enhance analytics, internal tooling, and developer productivity

Required Qualifications & Experience

• University degree in a STEM subject from a reputable institution
• Proven experience in a senior technical role such as Principal Engineer, Technical Architect, or equivalent position working with complex analytical system design
• Track record of owning, shaping and governing architecture across multiple teams and large-scale platforms
• Experience working with modern distributed and cloud-based systems
• Familiarity with our tech stack or equivalent technologies

Skills & Competencies

• Excellent architectural judgement, with the ability to balance short-term delivery needs against long-term technical strategy
• Strong problem-solving skills, particularly in complex, ambiguous, or high-impact technical scenarios
• Ability to communicate complex technical concepts clearly to both technical and non-technical stakeholders
• Ability to influence and drive technical direction and architectural decisions at a senior level
• Collaborative mindset, with the ability to work effectively across teams and senior stakeholder groups
• Pragmatic and outcome-focused, with a strong sense of ownership and accountability