Staff Implementation Engineer in London

At MatNex, our mission is to accelerate the change to net-zero through the disruption of materials discovery and production. As Staff Engineer, you will be the connective tissue across our entire technical organisation. You will raise the quality of everything we build, unify engineering thinking, and own the space between project deliverables that is so often where the most impactful work lives. Your role will span the breadth of our tech team, from scientific computing and quantum calculations to ML infrastructure and platform tooling. You will act as engineer, quality champion, systems thinker, and collaborator, working to maintain our excellent standards across the board rather than delivering within a single workstream. This is the perfect role for a senior engineer who wants both technical breadth and depth, real ownership, and the opportunity to shape how a fast-moving deep tech company builds software.

What you will be doing:

• Act as a floating senior resource across the ML and Scientific Computing teams, embedding wherever the need is greatest, contributing directly, and elevating those around you.
• Own code review throughput and quality across the engineering org, reducing the time changes spend waiting for a human to review and improving the overall speed of delivery.
• Identify and close gaps in developer experience, tooling, observability, and platform performance, tackling friction and speeding up our development cycles.
• Champion software development best practices: robust architectural thinking, comprehensive testing strategies, thorough documentation, and a culture of engineering excellence.
• Provide the systems-level perspective that keeps individual workstreams coherent as a whole, ensuring the parts being built by different teams fit together in the optimal way.
• Foster enhanced collaboration between the ML and Scientific Computing teams, improving cross-team visibility and shared understanding of what everyone is building.
• Identify opportunities for process improvement across the tech team, maximising our impact potential.
• Stay updated on industry trends and emerging technologies, and assess their potential impact on our roadmap.

About you:

• Exceptional modern Python skills. You should be among the strongest Python engineers in any room you walk into, and passionate about optimal use of the language.
• Demonstrated experience of systems-level thinking: you have designed and implemented systems that affected multiple teams, and you can speak clearly to the trade-offs involved.
• A track record of raising engineering standards, through code review, team culture, tooling improvements, documentation, or process, and the ability to articulate clearly what good and bad look like.
• Experience in multi-developer environments, with an eye for detail and a passion for building scalable, reliable software.
• The ability to balance hands-on engineering with strategic thinking, and this role requires both, often in the same week.
• Familiarity with Python scientific or numerical libraries (NumPy, SciPy, or similar) and comfort working in or around ML workflows.
• You may also have some experience with or desire to learn: ML infrastructure, distributed computing, or HPC environments.
• DevOps practices and cloud deployment (AWS or similar).
• Platform or infrastructure engineering, with a background where robustness, performance, and reliability were central concerns.
• High-performance languages such as C++ or Julia.
• Containerisation (Docker), monitoring tooling (Sentry, Grafana), or orchestration.

Our Benefits:

• Stock Options: We value our employees and want you to share in the success of the company. You will be a vested partner in our future achievements.
• Flexible holidays: 33 days annual leave/year which can be used on UK public holidays or on more convenient days for you.
• Fully covered comprehensive private healthcare and mental health support.
• Your birthday day off: Enjoy a well-deserved day off to celebrate and recharge.
• Work abroad: Travel the world while you get your job done, see family, or simply explore a new place!
• Enhanced Family & Carers leave to ensure you get that quality time in when you need it.
• Flexible work arrangements: our shared office space in Shoreditch is here to help foster collaboration and community. Most of the team is in 2 to 3 days a week, but we are happy to discuss alternatives as necessary.
• Continuous learning and growth: We're pioneers in our field, so you'll be encouraged to expand your knowledge and skills in new areas too.