Senior Software Engineer

Arqit; Belfast City District; On-site; GBP 65,000 - 90,000; Full time

Job summary

Arqit in Belfast invites world-class engineers to join a fast-moving product team delivering security software to customers. You will influence what we build next and ship code to customers within weeks, not quarters.

Beyond coding, you will shape product decisions, mentor juniors, and apply AI tooling across the development lifecycle, from design to deployment, ensuring resilience and performance. Join a globally distributed team with strong ties to universities, enabling mentoring, learning,

Qualifications

• Experience building scalable, enterprise software and services.
• Experience with hybrid architectures and cloud environments (IaaS/PaaS).
• Practical experience embedding AI tooling in the development lifecycle.
• Proficiency in Java, Kotlin, Rust, Python or C++.
• Experience with containers/virtualization and cross-platform development.

Responsibilities

• Join a fast-moving product team and ship code to customers within weeks.
• Help shape product decisions and mentor junior engineers.
• Extend AI tooling across the software development lifecycle from design to deployment.
• Monitor production changes and ensure resiliency and performance.
• Respond to issues flagged by internal teams or customers.
• Work within an agile methodology and deliver iteratively.

Skills

Enterprise software

Cloud IaaS/PaaS

AI tooling

Java/Kotlin/Python/C++

Containers/virtualization

Cross-platform

Communication/autonomy

Analytical problem solving

Job description

Join our growing team and become part of a close-knit, welcoming group of world-class engineers, who are passionate about building products that make a real difference.

Our team thrives on solving complex technical challenges and has a long history of delivering world-first cybersecurity solutions. With experience spanning Silicon Valley startups and large-scale multi-national corporations, our team offers an exceptional environment for mentoring, learning, and growth.

This spirit of innovation extends beyond our own walls: we maintain strong ties with Belfast's leading universities through collaborative research projects, and are now launching new initiatives in AI, networking, and encryption.

Our 100+ staff worldwide describe Arqit as succeeding in providing a positive and inclusive working environment, where staff feel that managers care about the success and well-being of their teams, and individuals feel valued as employees.

This is a rare chance to join Arqit, a global pioneer in quantum-safe encryption, at a pivotal moment of innovation and opportunity.

What you'll be doing

• Joining a fast-moving product team where your code ships to customers within weeks, not quarters, and you have influence over what we build next.
• Stretching beyond writing code, you will help shape product decisions, mentor junior engineers, and see the direct impact of your work when engaging with customers.
• Embracing AI tooling across the full software development lifecycle, from design and coding through to testing and deployment, focusing your time on the harder design problems, and getting the product right.
• Monitoring how your changes perform in production, and stepping in quickly to resolve any issues, so resiliency and performance are never in doubt.
• Responding swiftly and prioritising issues flagged by our internal teams, or raised by our customers.
• Working within an agile methodology, delivering value in short, iterative cycles.

What we're looking for

• Demonstrable experience building horizontally scalable, mission-critical enterprise software and services
• Experience with hybrid architectures and developing for cloud IaaS and PaaS environments.
• Practical experience using AI coding companions and embedding AI tooling across the software development lifecycle.
• Extensive experience developing with any of Java, Kotlin, Rust, Python or C++
• Experience working with containers, virtualisation technologies, and cross-platform development.
• Exposure to Linux or development for mobile platforms would be advantageous.
• Strong communication skills with a track record of taking ownership of results while working with high autonomy in fast-moving environments.
• Strong analytical, problem-solving, and organisational skills
• A genuine passion for technology and continuous self-development
• Adaptability, pragmatism, and the ability to thrive in a fast-moving environment

Please note: the ability to work without visa restrictions is ESSENTIAL.