All Locations
Peterborough
Advertising Salary
Competitive + benefits
Vacancy type
Permanent

About the role

PROIV is a mature, enterprise-grade low-code platform used by internal and external customers to build scalable, data-driven business applications where reliability and long-term maintainability are critical. The Core Engineering team is a small, highly experienced group responsible for evolving the platform’s foundational technology, including the C++-based PROIV Kernel and the Windows Developer IDE. This role focuses on developing and maintaining the core C/C++ codebase, modernising legacy code, and supporting build, test, and automation infrastructure. The team works collaboratively, follows modern engineering practices such as TDD, code reviews, CI, and secure coding, and is actively modernising its tooling and processes. This is an opportunity to contribute to a globally deployed product while helping shape a forward-looking engineering culture.

In this role your key responsibilities will be:

  • Contributing to the development and maintenance of the core C/C++ codebase, to support the ongoing evolution of the PROIV Kernel.
  • Improving and modernising legacy C code using modern C++ practices, to enhance performance, maintainability, and scalability
  • Learning and applying the PROIV language and environment, to support wider platform development when required.
  • Supporting and maintaining build tools and automation scripts, such as CMake and Python, to streamline development and testing workflows.
  • Writing clear, maintainable, and testable code, to ensure long-term code quality and ease of collaboration.
  • Participating in peer code reviews, to share knowledge and uphold coding standards.
  • Collaborating with quality assurance colleagues, to embed testing earlier in the development process.
  • Working independently to identify and resolve technical challenges, to maintain momentum and reduce bottlenecks.
  • Contributing to the continuous improvement of tools, processes, and delivery practices, to enhance team productivity and software quality.
  • Embedding modern software engineering practices across the team, to support a culture of technical excellence.

Skills & experience

  • Strong experience in C and C++, including the use of modern C++ techniques.
  • Proven good working knowledge and adherence to both the Core C++ Guidelines for writing modern, maintainable C++ and the CERT Secure Coding Guidelines to mitigate critical security vulnerabilities.
  • Proven ability to work with complex or long-standing codebases.
  • Comfortable working across both Windows and Linux environments.
  • Solid understanding of general software engineering principles and best practices.
  • Experience writing effective unit tests and working with test-driven development approaches.
  • Reasonable understanding of SQL and client/server architectures.
  • Self-motivated and proactive, with a willingness to take initiative.
  • Able to learn quickly and adapt to new tools, technologies, or environments.

Critical competencies:

  • Degree in Computer Science, Software Engineering, or a related discipline; or an industry-recognised equivalent qualification; or equivalent professional experience (minimum 3 years in software engineering, including at least 2 years using C/C++).
  • Familiarity with legacy codebases and approaches to modernisation.
  • Exposure to build systems and scripting tools such as CMake and Python.
  • Understanding of system internals or compiler/interpreter concepts is an advantage.
  • Strong analytical and problem-solving skills, with the ability to evaluate and balance design trade-offs effectively.
  • Solid experience working in a Test Driven Development environment.
  •  Working knowledge of the 'Shift Left' development philosophy, integrating quality and security practices early in the software development lifecycle, and a foundational understanding of threat modelling principles, specifically using the STRIDE methodology.

Benefits & culture

At Zellis we create market-leading HR & Payroll products and services, to power exceptional employee experiences so that you and your people do better. Our multi-award-winning products pay over five million employees a year, with almost half (42%) of the FTSE 100, 50% of the top retailers and 30% of the top universities in the UK & Ireland as customers, making us the largest provider of Payroll and HR software and managed services.

Our vision is to be the clear leader in pay, reward, analytics, and people experiences. We're passionate about creating an environment where people want to join, belong to, and be part of a progressive organisation. Our values, which were defined with input from all of our 2,000 colleagues, we live and breathe every day:

  • Unstoppable together.
  • Always learning.
  • Make it count.
  • Think scale.

Our people are critical to our ongoing success; we’re proud of our inclusive culture that gives you the platform to grow, challenge the status quo and play a crucial role in further enhancing our market position as the leading provider of HR & Payroll software and services. With Zellis you’ll have the chance to stretch and challenge yourself in an environment that’s varied, flexible and hugely supportive.

We also love to reward and recognise our brilliant colleagues. As part of your benefits package, you’ll receive:

  • A competitive base salary.
  • 25 days annual leave, plus your birthday off and the opportunity to buy additional holiday.
  • Private medical insurance.
  • Life assurance 4x salary.
  • Enhanced pension scheme with company contributions up to 8.5%.
  • A huge range of additional flexible benefits across financial & personal wellbeing, lifestyle & leisure.

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