Senior Software Engineer, Core Platform

Winston Fox; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Winston Fox is seeking a Platform Developer to help build shared engineering foundations across a global hedge fund. You will design and deliver backend services, frameworks and developer tooling that scale across many teams, establishing standard patterns for authentication, APIs and observability.

The role focuses on engineering leverage rather than client-facing apps, with an emphasis on production-grade platforms, reliability and scalable deployment across the firm’s infrastructure.

Qualifications

• Minimum 6+ years of Software Engineering experience with a platform mindset.
• Strong Python skills and backend/distributed systems background.
• Experience building internal developer platforms, service frameworks, or developer tooling.

Responsibilities

• Design and build reusable backend services, APIs, and service frameworks used across teams.
• Develop libraries, utilities, and platform components to accelerate product development.
• Define authentication, authorisation, observability, logging and error-handling patterns.
• Create templates and paved-road workflows to enable rapid, safe deployment of new systems.
• Improve developer experience via automation, tooling, and better onboarding.
• Contribute to CI/CD, monitoring, production engineering, and shared systems improvement.

Skills

Platform mindset

Python

Backend engineering

Distributed systems

Internal tooling

DevOps mindset

Tools

Docker

Kubernetes

CI/CD

Cloud infrastructure

Job description

How do you build a technology platform that allows hundreds of engineers to move faster without sacrificing reliability, security or engineering quality?

We are partnering with a leading global multi-strategy hedge fund that is investing heavily in the evolution of its core technology platform.

They are looking for an exceptional Platform Developer to help build the shared engineering foundations used across the firm – creating the services, frameworks, APIs and developer tooling that sit underneath a broad range of investment and business-critical technology.

This is not an application development role, nor is it traditional DevOps. It is a Software Engineering position focused on engineering leverage: building technology once, building it exceptionally well, and enabling multiple teams across the organisation to benefit from it.

The Challenge

As the firm's technology organisation continues to scale, individual engineering teams shouldn't need to repeatedly solve the same fundamental problems.

How should a new service be structured?

How should applications authenticate?

How should APIs behave?

How should services be deployed, monitored and supported?

How can engineers move from an idea to production faster and more safely?

Your job will be to help solve these problems at the platform level. You'll design and build reusable backend services, frameworks, libraries and tooling that establish common engineering patterns and create a paved road for development teams across the firm.

What You'll Be Building

• Designing shared backend services, APIs and service frameworks used by engineering teams across the organisation.
• Building reusable libraries, runtime utilities and common platform components.
• Developing standard approaches to authentication, authorisation, API design, observability and error handling.
• Creating service templates and paved-road workflows that allow engineers to build and deploy new systems faster.
• Improving the internal developer experience through automation, tooling, documentation and better onboarding.
• Establishing engineering standards around architecture, deployment, monitoring and operational support.
• Building platform capabilities that improve reliability and consistency across multiple engineering teams.
• Contributing to CI/CD, debugging, production engineering and the continued improvement of shared systems.
• Exploring how AI-assisted engineering and LLM-powered developer tooling can meaningfully improve software development productivity and quality.

You'll work closely with Software Engineers, Infrastructure, Security and other technology teams, giving you significant visibility and influence across the wider engineering organisation.

Engineering Environment

The environment is primarily centred around:

Python | FastAPI | APIs | AWS | Docker | Kubernetes | CI/CD | Observability | Distributed Systems

Python is particularly important. This isn't scripting or automation-heavy Python – they want engineers capable of designing and building high-quality production software, services and frameworks.

The wider remit is intentionally broad, however. You'll be expected to think beyond an individual language or technology and understand how good engineering platforms should work at scale.

What We're Looking For

• We're interested in strong Software Engineers who have developed a genuine platform mindset.
• You will likely have a minimum of 6+ years of Software Engineering experience, with strong Python skills and a background spanning backend engineering, distributed systems, developer platforms or internal engineering tooling.
• You should understand how to build production-grade services and APIs, with knowledge across areas such as service architecture, authentication and authorisation, observability, logging, monitoring and resilient system design.
• Experience with Docker, Kubernetes, cloud infrastructure and modern CI/CD will also be important.
• Previous hedge fund experience is not essential. However, we are looking for someone with experience building sophisticated platforms at high-quality firms
• Experience building internal developer platforms, service frameworks, reusable libraries, engineering portals, or developer tooling would be particularly relevant.

Why This Role?

• The interesting thing about Core Platform Engineering is the multiplier effect.
• You're not simply building another application.
• You're building the technology that allows other engineers to build better applications.
• A great framework, service or piece of developer tooling might ultimately influence dozens of systems and hundreds of engineers across the organisation.
• You'll join a sophisticated global engineering environment where technology is central to the business, while still having the autonomy to solve difficult problems, challenge existing approaches and influence how the firm's engineering platform develops.
• For a strong Software Engineer who enjoys building foundational technology, improving developer experience and solving engineering problems at organisational scale, this is an opportunity to have impact far beyond a single system or team.