Senior Software Engineer in London

Polaron is a spin-out from Imperial College London, founded by Dr Isaac Squires, Dr Steve Kench, and Dr Sam Cooper. The founders share a mission: to harness engineering, artificial intelligence, and materials science to design the materials of the future. Our vision is to become the world leader at the interface between AI and materials, combining scientific rigour with engineering pragmatism to enable the next generation of sustainable, high-performance materials. Our work isn’t just about hard, scientific problems – it’s about the urgency and impact of solving them. Advanced materials underpin all aspects of modern life: from the batteries that power electric vehicles to the alloys used in turbines and the composites that make aircraft lighter. Accelerating how these materials are developed, designed, and manufactured has a direct impact on the world’s ability to build a more sustainable future.

We’re developing a cloud-based SaaS platform that empowers materials engineers to use state-of-the-art image-based AI without friction, helping them generate insights and accelerate innovation with minimal effort.

Stack: TypeScript, React, Next.js, Express, Prisma, Python (PyTorch), PostgreSQL, Docker, Kubernetes, AWS, Terraform

What we’re building:

• A data-intensive visual interface that enables users to explore, interact with, and analyse complex datasets (including high-resolution image data) directly in the browser built for performance and fluidity at scale.
• Interactive visualisation and analysis tools that combine 2D, 3D, and graph plotting.
• A computational orchestration layer that connects the frontend experience with machine learning models, allowing users to run sophisticated analyses and simulations seamlessly.
• Scalable AI infrastructure for training, serving, and executing complex machine learning workflows across distributed environments.

Why we’re hiring: We’re entering a phase of rapid product and infrastructure scaling. To support this growth, we’re hiring a Senior Software Engineer who will help define the technical foundations of our platform, shaping everything from backend architecture to product performance and developer experience. This is a hands-on, high-ownership role for someone who wants to build the core technology that enables the world’s most advanced materials to be developed and manufactured. You’ll have the freedom to make architectural decisions, work closely with scientists and engineers, and see your code directly power breakthroughs in industry and research. This role reports directly to our Head of Engineering and offers a significant degree of autonomy and influence over technical decisions and product direction.

A snapshot of your first 6 months at Polaron:

• Month 1 – Understand and Contribute: Quickly develop a deep understanding of our product, systems, and users. Deliver incremental improvements to our product or platform. Share early insights to help shape technical and product decisions.
• Month 3 – Take Ownership: Lead the design and delivery of an end-to-end feature that provides clear customer value. Collaborate cross-functionally with ML and product teams to turn complex ideas into working software. Support and mentor junior engineers through code reviews, pairing, and guidance.
• Month 6 – Drive Impact: Demonstrate strong technical and product judgment, independently shaping and improving complex systems. Take ownership of key architectural areas or projects. Contribute to better engineering practices, tooling, and team efficiency.

Our hiring process:

• Intro Call (20 min) get to know you, your experience, and your motivation.
• Technical Pairing (1 hr) collaborative coding session over video call.
• Paid Trial Day work with the team on a real engineering challenge (remote or onsite).
• Final Debrief & Offer.

We value transparency and fast feedback at every step.

Requirements: You are an experienced engineer who loves building robust, elegant systems that serve real product needs.

• 5+ years’ experience as a product-focused software engineer.
• Experience writing well-tested, maintainable code in a statically-typed language (TypeScript, Go, Rust, Java/Scala...).
• Strong fundamentals in API design, database modeling, scalability, and system performance.
• Experience deploying and maintaining systems on AWS, using tools such as Terraform, Docker, and Kubernetes.
• The ability to work across the stack when needed but with a clear backend focus (data, APIs, infra).
• Excellent communication skills: you can explain complex technical concepts with clarity.

Bonus points:

• Experience building high-performance canvas or visualization interfaces (D3, Observable Plot).
• Exposure to PyTorch or machine-learning pipelines.
• Knowledge of on-prem or hybrid cloud deployments.

Mindset and values:

• Is product-oriented: you care about impact, not just elegant code.
• Is scientifically curious and thrives on complex, technical challenges.
• Works with low ego and collaborates transparently.
• Enjoys autonomy but knows when to ask questions and seek alignment.
• Has a long-term mindset: ready to help build a company, not just a product.
• Communicates openly and values shared learning.

Team and culture:

• High trust and ownership.
• Pragmatism over dogma.
• Curiosity, humility, and scientific discipline.
• A strong focus on quality, impact, and long-term maintainability.

What we value at Polaron:

• STEM mindset: genuine curiosity for science and the physical world.
• Hunger to learn: proactive, self-driven, and impact-oriented.
• Pragmatism: you prefer solutions that work over theoretical perfection.
• Low ego & empathy: you lift others up, you listen, you share knowledge.
• Long-term commitment: you want to grow with the company and shape its journey.

Benefits:

• Salary: £100,000 - £140,000 depending on experience.
• Equity: meaningful stock options in a growing company.
• Holidays: 25 days + 2 "festive leave" days.
• Perks: gym membership, free barista coffee.
• Location: Shoreditch Exchange (Hoxton, London).