Principal Software Engineer

Principal Software Engineer

Department: Engineering

Employment Type: Full Time

Location: Manchester, UK

Interact provides enterprise-grade intranet software that connects over three million employees to leading global names like Levi's, Domino’s, Teva Pharmaceuticals, and Technicolor.

Our team of customer‑focused problem solvers are passionate about helping organizations to communicate better. We do this together by constantly working to improve every service and product we offer. With offices in Manchester, New York, Dubai, Tulsa, and Warsaw, we operate across North America, EMEA, and Australia.

Click on any of our vacancies and you’ll see one thing in common – they all begin with this message. Why? Because at Interact we treat everyone with the same respect and honesty. Whether you’re a developer fresh out of college or a seasoned salesperson, we live the motto that we uphold for our customers: our people are our most valuable assets.

We are looking for a Principal Software Engineer, who will be a hands‑on engineer responsible for fast development of strategic functionality, AI integrations in the core product, shaping the architecture, driving engineering excellence, and delivering complex features across our platform used by millions of users globally.

A core part of the role is end-to‑end execution of AI integrations into our existing ecosystem, including architecture, implementation, governance, and enablement across squads.

You will combine deep technical capability with strong leadership influence—mentoring engineers, guiding technical strategy, and personally contributing high‑quality code across our stack (C#, ASP.NET, React

JS, Node.js, SQL Server, AWS).

• Design, build, and ship high‑quality, production‑grade software using C#, ASP.NET, React
  
  JS, Node.js, SQL Server, and AWS services.
• Serve as a hands‑on architect/engineer—writing foundational code, delivering end to end features, validating technical approaches through prototypes and spikes, and leading design discussions.
• Maintain deep familiarity with our codebase and actively contribute to critical, high‑impact features and refactoring initiatives.
• Define and uphold engineering standards across squads, including SOLID, design patterns, secure coding, and observability principles.
• Evaluate technical trade‑offs, performance implications, and long‑term maintainability to steer architectural direction.

• Lead and implement AI‑powered features across Interact’s ecosystem, to fuel value creation (eg. intelligent search, summarisation, classification, recommendation systems, generative capabilities, experience augmentation, insights generation, etc.)
• Develop secure and scalable AI integration layers using modern patterns (embeddings, RAG, vector databases, prompt orchestration, evaluation frameworks).
• Build and maintain AI‑related services, APIs, and backend components—including telemetry, evaluation pipelines, and guardrails.
• Establish best practices for responsible AI, including privacy, compliance, red‑team, fallback logic, and model governance.
• Partner with Product to prioritise AI initiatives and define measurable success metrics for user experience and business impact.
• Create reusable AI components, SDKs, documentation, and guidelines for wider engineering use.

• Lead cross‑team initiatives, unblock complex technical challenges, and ensure architectural alignment across the organisation.
• Work closely with Product & Delivery Managers to refine requirements, shape roadmaps, and ensure predictable delivery.
• Break down complex problems and guide teams through execution—participating directly in coding when needed.

• Champion testing excellence: author and maintain unit tests, integration tests, and Playwright E2E tests.
• Work closely with Dev Ops to optimise CI/CD pipelines (Team City, Octopus Deploy) and improve deployment reliability.
• Conduct in‑depth code reviews, provide hands‑on pairing, and ensure code quality across multiple squads.
• Optimise performance across APIs, databases, caching, distributed systems, and front‑end rendering.

• Maintain hands‑on involvement in resolving complex production issues, running post‑mortems, and…