Senior .NET Engineer – Perm or Contract

Our ‘black belt’ specialists are leaders in their domains: digital champions, delivery-focused experts, top-tier security professionals, AI thought leaders, and engineering best practice advocates.

With a global footprint and deep local insight, Software at Scale delivers cutting-edge technology solutions that power mission-critical platforms. We solve complex engineering challenges at scale, driving quality, performance, and resilience through the strength of our people.

Empower Your Career

We’re seeking a highly proactive Senior .NET Engineer to play a key role in delivering high-quality, scalable systems across our most important programmes. This mandate focuses on building ultra-fast, highly performant backend architectures using the latest .NET Core frameworks and C# within a highly secure enterprise environment.

This role is hands-on and delivery-oriented. Your primary focus will be engineering robust, highly scalable RESTful JSON APIs that serve as the backbone for our digital products. We are looking for an engineer who doesn’t just execute requirements but actively thinks outside the box to solve complex problems in creative ways. You will have the scope to heavily influence backend architecture, establish performance baselines, and drive technical excellence within our engineering teams.

Key Responsibilities

• Proactive Problem Solving: Act as a technical catalyst within the team. Autonomously identify architectural bottlenecks or process inefficiencies, thinking outside the box to engineer creative, unconventional solutions to complex technical challenges.
• API Architecture & Engineering: Design, build, and scale production-grade RESTful JSON APIs using the latest .NET Core frameworks and C#, ensuring optimal response times and high throughput.
• Backend System Design: Contribute heavily to backend architecture and solution design, supporting enterprise-scale requirements, microservices, and complex data orchestration.
• Secure Development: Architect solutions that adhere to the strictest security standards, working safely within a highly regulated enterprise environment to protect sensitive data and prevent vulnerabilities (e.g., OWASP top 10, secure token handling).
• Optional GraphQL Integration: While the core focus is REST, you will help design and integrate GraphQL endpoints where they provide distinct advantages for specific data fetching and aggregation needs.
• DevOps & Testing: Develop and maintain CI/CD pipelines using GitHub Actions or TeamCity. Implement robust test automation practices (xUnit, NUnit), including containerised workflows using Docker.
• Cloud-Native Deployment: Leverage AWS-native services (e.g., ECS, RDS, API Gateway) to deploy reliable, scalable .NET applications.
• AI Tooling Adoption: Champion the adoption of GenAI and agentic tools where they tangibly improve engineering productivity, code quality, or system capability.
• Observability: Apply observability best practices using modern monitoring, logging, and tracing tools to proactively manage system performance and identify bottlenecks.
• Technical Mentorship: Participate in code reviews, architectural discussions, and performance optimisation efforts. Support and mentor mid-level engineers, contributing to a culture of uncompromised quality and ownership.

What You Bring

• Creative & Proactive Mindset: You are a self-starter who doesn’t wait to be handed the answer. You excel at thinking outside the box and applying creative problem-solving skills to overcome complex engineering constraints.
• Senior-Level Expertise: Proven experience operating at a Senior Engineer level within modern, high-performing engineering teams.
• .NET Mastery: Deep, hands-on expertise in C# and the latest .NET Core frameworks. You understand the internals of the CLR, memory management, and asynchronous programming.
• RESTful API Excellence: Mandatory, extensive commercial experience designing, documenting (Swagger/OpenAPI), and building high-performance RESTful JSON APIs from scratch.
• Security & Performance: A strong track record of building secure, performant applications (optimising database queries with EF Core/Dapper, caching strategies) specifically within highly regulated environments.
• Infrastructure & CI/CD: Experience deploying and operating .NET workloads on AWS, managing CI/CD pipelines, and working with Docker containers.
• AI Fluency: Exposure to GenAI and agentic engineering tools, with a practical, delivery-focused mindset on how to use them safely.
• Bonus Skills: Commercial experience integrating or building data layers using GraphQL (e.g., HotChocolate) is highly desirable but not strictly mandatory.
• Communication: Strong communication skills and a collaborative, execution-driven approach to solving enterprise problems.

What We Offer

• Meaningful, hands-on engineering work across complex, enterprise-grade platforms.
• Clear growth pathways from Senior to Staff and beyond.
• A low-ceremony, delivery-focused environment that values engineers who own outcomes.
• Competitive remuneration and benefits.
• The opportunity to work alongside highly experienced engineers on challenging, high-impact systems.