Principal Software Engineer

Join One Advanced

Principal Software Engineer

Location: Hybrid
Employment Type: Full Time

About the role

We are looking for a Principal Software Engineer to provide senior technical leadership across our engineering teams. This is a hands‑on role for someone who combines strong architectural thinking with the ability to deliver high‑quality production software.

You will shape technical standards, design complex systems, and guide engineering teams to ensure solutions are robust, scalable, and aligned with business goals. You will play a key role in maintaining engineering excellence while supporting the growth of those around you.

This role offers the opportunity to shape technical direction, influence engineering standards, and deliver meaningful impact across the organisation.

• Lead the design and architecture of complex software systems
• Set and uphold technical standards, coding practices, and quality benchmarks
• Provide technical leadership and guidance to development teams
• Contribute hands‑on to the design, development, and review of production code
• Work closely with product managers, designers, and other stakeholders to translate requirements into technical solutions
• Mentor and support engineers at different stages of their careers
• Resolve complex technical challenges and provide direction on critical issues
• Drive continuous improvement through modernisation, automation, and adoption of best practice

• Extensive experience in software engineering within complex environments
• Strong proficiency in languages such as C++, Java, Python, or .NET
• Proven experience designing distributed systems, microservices, and cloud‑based solutions
• Solid understanding of system design, automated testing, and modern development practices
• Strong analytical and problem‑solving capability
• Experience influencing technical direction and leading engineering discussions
• Clear communication skills and the ability to work effectively across technical and non‑technical teams
• A commitment to quality, continuous learning, and professional development

Wellbeing that means something

• 26 days’ holiday + bank holidays (and the option to buy more) plus 1 paid volunteering day every year
• Exceptional family leave
  , 26 weeks fully paid maternity/adoption, 4 weeks fully paid paternity, 22 weeks fully paid shared parental leave, plus 5 days paid bereavement leave
• Robust sick pay of up to 13 weeks full pay + 13 weeks half pay
• 24/7 Employee Assistance Programme for confidential support
• Private medical insurance for everyone
  , no medical‑history exclusions

Financial benefits that have your back

• Performance‑based rewards tailored to your role
  , from company‑wide bonuses to OTE and commission structures
• Income protection
  : up to 75% salary for 5 years if you ever need it

Grow your career with us

• Skills Hub learning platform with leadership pathways, future‑manager training, and a huge online library
• Access to external training and apprenticeships

Making a Difference

• Match It!Fundraise for a cause close to your heart and One Advanced will match part of the funding
• Pennies from Heaven
  donate the pennies from your pay check to help make a difference without lifting a finger

Plus plenty other flexible benefits to suit your lifestyle on our Reward Hub, including:

• ULEV car scheme with 1,000+ models
• Dental insurance, Health Cash Plan, Critical Illness Cover, Partner Life Cover

At One Advanced, we are at the forefront of delivering sector‑focused technology solutions that simplify complexity, drive meaningful progress, and help build a fairer, more inclusive society. We’re much more than a software company. We deliver SaaS workflow applications and IT services that power organisations across Education, Government, Healthcare, Legal, Manufacturing, Housing, Retail, and more.

One Advanced is one of the UK’s largest business software and services companies. Based in Birmingham (The Mailbox), operating across the UK, Ireland, India, and Australia. Our secure, scalable platform, including One Advanced AI, our private AI service for UK organisations, powers connectivity and innovation across critical sectors. Alongside our software are our IT services, including hosting, managed services, and application modernisation.

We strive to create an inclusive workplace that drives innovation and collaboration, championing diverse perspectives and ideas. Our Environmental, Social and Governance (ESG) strategy is embedded in everything we do, guiding us to create meaningful impact for our people, our customers and the planet.

Join us and become part of a team that’s powering the world of work and making a real difference.

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