
PhysicsX · New York City or London
The Role
As a Principal Security Engineer, you will partner closely with engineering teams to design and implement secure development practices, integrate security into our CI/CD pipeline, and lead security and design reviews.
You’ll bring deep expertise in DevSecOps, application security, hands-on experience securing web applications and APIs, and a strong understanding of modern development workflows. This is a unique opportunity to shape the future of our security program while working in a high-ownership, high-impact environment.
What you will do
What you bring to the table
Nice to Have Skills
What we offer
Build what actually matters
Help shape an AI-native engineering company at a formative stage, tackling problems that genuinely matter for industry and society. This is work with real-world impact - and something you can be proud to stand behind.
Learn alongside exceptional people
Work with a high-caliber, collaborative team of engineers, scientists, and operators who care deeply about doing great work, and about helping each other get better. We come from diverse backgrounds, but we share a commitment to operating at the highest level and addressing some of the most complex challenges out there. If you’re ambitious, thoughtful, and driven by impact, you’ll feel at home.
Influence over hierarchy
We operate with a flat structure: good ideas win - wherever they come from. Questioning assumptions and challenging the status quo isn’t just welcomed, it’s expected.
Sustainable pace, long-term ambition
Building meaningful technology is a marathon, not a sprint. We believe in balancing focused, ambitious work with a life beyond it. Our hybrid model blends time together in our New York office with work-from-home days, giving you the flexibility to work sustainably while staying connected in person.
UK Benefits:
Equity options; 10% pension employer contribution; 25 days holiday plus public holidays; private health insurance; enhanced parental leave; free lunch onsite
US Benefits:
🚀 Equity options - share meaningfully in the company you’re helping to build.
💰 5% contribution to 401(k) - build long-term security with a strong retirement plan.
🍽️ Free team lunch 1x/week - good food, great company, and space to connect.
🏥 Private health insurance – comprehensive cover for you, offering total peace of mind.
👶 Enhanced parental leave – 3 months full pay paternity and 6 months full pay maternity leave, to provide extra flexibility during the moments that matter most.
☀️ 20 days of Annual Leave (+ Public Holidays) - because taking time to rest matters.
📈 Personal development – dedicated support for learning, development, and leveling up over time.
💪 Gympass / Wellhub (subsidized) – for you and up to 3 family members, supporting both physical and mental wellbeing.
💳 Flexible Spending Account (FSA) – set aside pre-tax dollars for eligible healthcare expenses.
🔎 Watch this space, we’re continuing to build this as we grow…
Salary for this position in the USA is from $200,000 to $300,000
PhysicsX is a physical AI company on a mission to accelerate innovation and overhaul what engineering and manufacturing look like today. We are building a new software stack to deliver deep AI enablement across the entire engineering lifecycle. We partner with leading organizations in aerospace & defense, automotive, semiconductors, materials, and energy & renewables, supporting them on some of their most critical and complex challenges. PhysicsX is headquartered in the United Kingdom, with offices in London and New York. Last year we raised $155 million as part of its Series B financing. The round was led by Atomico, with participation from Temasek, Nvidia, Siemens, Applied Materials, and July Fund, as well as continued support from existing investors including General Catalyst, NGP, Radius Capital, Standard Investments, and Allen & Co. Learn more about how we work: https://www.physicsx.ai/careers .
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