Backend Engineer London, UK

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.

Our key stats:

• Team of 12 people today, growing fast.
• Based in East London (Shoreditch Exchange, Hoxton).
• Backed by cutting edge research and strong industry partnerships.
• Stack: TypeScript, React, Next.js, Express, Prisma, Python (PyTorch), PostgreSQL, Docker, Kubernetes, AWS, Terraform.

What we're building:

At Polaron, we're building the next generation of tools that enable materials scientists and manufacturers to leverage state of the art AI vision models, all without ever leaving their web browser.

Our application consists of:

• Adata 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.
• Acomputational 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, we're hiring a Backend Software Engineer to strengthen the performance, scalability, reliability, and security of our platform.

This role is for an engineer who enjoys building robust, well structured systems that make complex applications simple to operate and scale. You'll work across our cloud and backend stack - designing APIs, improving infrastructure, and building the systems that enable our customers to interact with powerful AI models at scale.

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

• Learn Polaron's backend architecture, cloud environment, and deployment stack
• Ship your first small, incremental changes to our systems
• Get comfortable with our workflows for monitoring, testing, and releasing

Month 3 - Take Ownership

• Design, implement, and maintain backend systems supporting key product features
• Improve reliability and performance of a core service (e.g. API, image processing, or orchestration)
• Contribute to our observability and monitoring systems

Month 6 - Drive Impact

• Independently improve the scalability, performance, and reliability of key systems
• Strengthen system security and automate testing and deployment pipelines
• Influence our infrastructure and architecture roadmap

Our hiring process:

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

We value transparency and fast feedback at every step.

You are an experienced backend engineer who builds reliable, maintainable, and secure systems.

You have:

• 4+ years of experience as a backend focused engineer.
• Strong skills in TypeScript, Node.js, and SQL (or similar technologies).
• Solid experience working with cloud providers such as AWS (or equivalent platforms like GCP or Azure), and developing software designed for deployment in these environments.
• Experience working with continuous integration and deployment pipelines, and with common cloud technologies such as Docker and Kubernetes.
• Proficiency in designing, documenting, and maintaining APIs and services.
• Comfort balancing quick iteration with reliability and long term maintainability.

Bonus points for:

• Experience with Python (for ML or data workflows).
• Infrastructure as Code tools such as Terraform.
• Familiarity with security engineering, and compliance frameworks (e.g. ISO 27001, SOC 2).
• Experience working with GPU workloads or building highly resilient distributed systems.

Mindset and values:

We're looking for someone who:

• Cares deeply about system reliability and performance
• Enjoys automating repetitive tasks and improving developer velocity
• Is pragmatic - focused on what works over dogmatic processes
• Thrives on collaboration and transparent communication
• Balances autonomy with alignment; knows when to ask for clarity
• Has a continuous improvement mindset, eager to make the stack faster, safer, and simpler.

Team and culture:

You'll join a small, tight knit group of engineers and scientists who are building Polaron's product and culture together. We operate with:

• 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:

• 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.

• Salary: £75,000- £95,000 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)