Principal Software Engineer

.Net, PHP, Umbraco, Drupal About

The Role A Principal Engineer is the most senior technical role in manifestos engineering team , providing leadership when it matters most: whether shaping a new client opportunity, designing complex architecture or resolving a critical live issue. You will work across our client estate rather than being embedded in a single project, moving between platforms and codebases as the work demands.

You will hold technical authority across our core stacks, .NET and Umbraco, PHP and Drupal, alongside the cloud infrastructure and hosting platforms that sit underneath them. The role has three sides to it. You help shape technical solutions through discovery, technical qualification and solution design. You steer delivery on our most complex projects, setting the architectural direction and lifting the standard of the engineering around you.

And you are the person who can drop into an unfamiliar codebase under pressure and diagnose what is actually happening, giving both our teams and our clients confidence at the moments that matter most. We build digital products for charities, non-profits and membership and visitor organisations. Our clients are purpose-led, often working with constrained budgets, and the platforms we build carry donation journeys, supporter data and services people depend on.

Technical decisions here have real consequences, and this role exists to make sure we get them right. Responsibilities Provide technical authority across our client estate, spanning multiple platforms, hosting environments and codebases. Shape technical solutions for new business, from initial qualification through discovery to solution design and estimation. Lead the architecture of our largest and most complex client projects. Act as the senior technical escalation point for live incidents and complex problems, across multiple stacks.

Raise the standard of engineering across the department through mentorship, technical review and setting clear standards. Build client confidence by representing us credibly with senior technical stakeholders. You set and hold the technical direction on our most complex work You define architecture that is appropriate to the client's budget, team and long-term maintenance capability, not to the most interesting technical solution available.

You uphold a clear software design philosophy and ensure teams deliver maintainable solutions. You have a clear understanding of simplicity. You define solutions that are simple by design and challenge requirements that introduce unconsidered complexity. You identify and challenge ineffective practices in delivery teams and in client organisations. You delegate, and maintain clear separation from work that should be considered routine.

You make hosting, infrastructure and platform decisions with a clear view of cost, security and who will be responsible for what after launch. You are the senior technical escalation point across the estate You diagnose and resolve complex problems in codebases you did not write and may not have seen before. You lead the technical response to significant incidents, establishing root cause and directing remediation.

You give clients and internal teams confidence at the point where things have gone wrong, through clear communication and visible control of the situation. You identify the systemic causes behind recurring problems and drive the changes that stop them repeating. You raise the standard of engineering across the department You are an active and visible technical leader across the company.

You mentor lead and senior engineers, building capability rather than absorbing the hard work yourself. You contribute to and uphold our engineering standards, technical governance and software development lifecycle. You demonstrate your passion for keeping on top of current tools, standards and trends, including AI-assisted engineering practice. You support marketing and new business with prototypes, thought leadership or presentations where it plays to your strengths.

You create learning within the team by specifying solutions that further our collective knowledge and give others opportunities to grow. About You Professional knowledge and experience Cross-stack technical depth. Genuine working expertise across more than one platform and language, specifically .NET and Umbraco alongside PHP and Drupal. Comfortable holding technical authority in both rather than being deep in one and passing in the other.

Architectural leadership. Expert in designing robust, scalable and secure architectures for content-managed platforms, integrations and modern web applications. Cloud and infrastructure. Practical, hands-on experience with cloud platforms, particularly Azure, including CI/CD pipelines, infrastructure as code and managed hosting environments. Enough depth to make infrastructure decisions and resolve infrastructure problems with minimal support. Diagnostic ability under pressure. Proven ability to…