R & D Senior Software Engineer

Nucleus Security is an enterprise leader in vulnerability and exposure management, providing a platform that unifies security data to help organizations prioritize and mitigate risks faster.

Nucleus Security

Employee count: 51-200

United Kingdom only

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R&D Senior Software Engineer

Are you looking for more in life than just building another web app? Does upending cyber security resonate with you? We're a rapidly expanding cybersecurity startup revolutionizing vulnerability management for organizations of all sizes. For our customers, vulnerability management has always been a game of catch-up, with limited asset coverage and manual processes. Nucleus' primary mission is to create a fast, scalable platform that not only addresses these challenges but also makes vulnerability management simple, fun, and effortless. Currently, we're looking for a passionate Senior Python Software Engineer to join our growing team of engineers.

About Nucleus Security
Nucleus Security is transforming how security and development teams manage vulnerabilities at scale. Our platform unifies vulnerability data across scanners and environments, enabling organizations to prioritize and remediate vulnerabilities efficiently. We work with some of the most security-forward enterprises, empowering them with tools that accelerate secure software delivery and infrastructure hardening.

Role Overview
As a Senior Software Engineer in our Engineering team, you'll operate at the frontier of innovation, taking early ideas and high-level product vision and translating them into real, impactful software.

You’ll work closely with product and security experts to design and build new features, services, and tools that push the boundaries of what’s possible in vulnerability management.
This role offers a balanced blend of backend and frontend development, with approximately 50% of your time spent architecting scalable backend systems and the other 50% dedicated to crafting dynamic, user-focused frontend experiences.

What You’ll Do
-You will work with the Founders, multiple members of the R&D team, and the engineering team to develop new, experimental technologies as part of Nucleus’ innovation mission.
-The core responsibility is to develop our new to market, AI-driven vulnerability intelligence platform and data feed. Take ownership of design, implementation, an deployment in conjunction with the R & D team.
-Collaborate with cross-functional teams across the globe, each working in different technology stacks.
-Build scalable backend systems using Python (Django) and MySQL or SingleStore.
-Develop dynamic and responsive user interfaces with TypeScript, React and Tailwind.
-Investigate and incorporate emerging trends in cybersecurity into product ideas.
-Write clean, maintainable, and well-tested code.
-Participate in architectural discussions and code reviews.

What We’re Looking For
Required Experience

- 5+ years of professional software engineering experience.
- Proven ability to thrive with minimal direction, especially in ambiguous or R&D-heavy environments.
- Strong backend development experience with Python, Django 4.2, and the Django REST Framework.
- Solid front-end development experience with TypeScript + React 19
- Experience with relational databases, especially MySQL.
- Experience with docker and containerization.
- Experience working in a cloud environment, ideally AWS.
- Familiarity with Agile/Scrum methodologies in a professional setting.
- Mindset: Creative thinker who enjoys solving hard problems and experimenting with novel soluntions.
- Cyber Security Passion: Demonstrated interest or background in cybersecurity. Experience in vulnerability management, threat intelligence, or related domains is highly desirable.

Preferred Experience

- Engineering team lead experience
- Experience working on multiple projects at the same time
- Experience with big data analytical systems such as Big Query, Redshift, Snowflake, Databricks, SingleStore, etc...
- Experience working with vulnerability scanning technologies on any part of the tech stack (e.g., SCA, SAST, DAST, IAST, VM Scanning, Container, etc.)
- Experience maintaining applications on Linux platforms in cloud environments.

Why You Should Be Excited

Nucleus is a truly unique solution that’s defining a market AND making an actual impact. 
We’re biased, but you will get to work with one of the best teams in security.We have a lot to get done and we work extremely hard, but we have fun in the process. 
Work with a high-performing team that values creativity, autonomy, and innovation.
Collaborate on meaningful products that improve the security posture of major organizations.
Enjoy flexible remote work arrangements and a strong emphasis on work-life balance.

Additional Information
At Nucleus we are committed to achieving excellence in our field by combining diversity, collaboration, teamwork, and pride in our work. All qualified applicants will receive consideration for employment without regard to race, sex, color, religion, sexual orientation, gender identity, national origin, protected veteran status, or disability.

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About the job

Apply before

Dec 01, 2025

Posted on

Oct 02, 2025

Job type

Full Time

Experience level

Senior

Location requirements

United Kingdom

Hiring timezones

United Kingdom +/- 0 hours

About Nucleus Security

Learn more about Nucleus Security and their company culture.

View company profile

What began as a practical solution to a complex problem for a pair of Department of Defense security experts has evolved into a leading force in the cybersecurity landscape. Nucleus Security was born from the firsthand experience of its founders, Steve Carter and Scott Kuffer, who were grappling with the unwieldy and inefficient nature of manual vulnerability management. They envisioned a more streamlined, automated, and intelligent way for organizations to handle the relentless onslaught of security threats. This vision materialized into a platform designed by practitioners, for practitioners, with the core mission of transforming how enterprises and government agencies prioritize and mitigate risks at scale.

The journey started with a clear goal: to build a centralized hub that could unify disparate vulnerability data, automate cumbersome workflows, and ultimately empower security teams to act faster and more decisively. Early on, the focus was on creating a tool that could make sense of the chaotic influx of information from various security scanners and tools. This commitment to unification and automation quickly resonated with organizations struggling to keep pace with the evolving threat landscape. Today, major corporations like Motorola, Paychex, and Mastercard rely on Nucleus to bring clarity and control to their vulnerability management programs. The platform's ability to integrate with over 160 security and business tools allows it to serve as a single source of truth, breaking down data silos and providing a comprehensive view of an organization's risk posture. This success has not gone unnoticed, with Nucleus being recognized on the Deloitte Technology Fast 500 as one of the fastest-growing companies in North America, a testament to its innovative approach and the critical need it addresses in the market.