Lead Backend Engineer - .NET

We are seeking a Lead Backend Engineer (.NET) for a senior, hands-on role as a key Individual Contributor. In this position, you will write production-ready C# code daily while shaping the overall .NET Core and ASP.NET Web API architecture. You will own the design of secure, scalable APIs, third-party client integrations, and high-throughput data processing systems.

As one of the strongest individual contributors, you will be working closely with the company Founders on technical strategy, you will champion engineering excellence and mentor the growing development team. This role spans multiple client projects across diverse industries. You will be the senior technical voice who takes full ownership of cloud infrastructure (Azure / AWS) and production system behaviour. If you excel at building robust backend services, establishing modern engineering standards, and guiding technical project delivery, apply today.

Responsibilities

· Mentor and coach other developers: set the bar for code quality and engineering practice, help them grow into harder problems, and take the technical lead where it makes sense

· Own technical direction and architecture across client projects: domain modelling, service boundaries, data flow design

· Design, build, and maintain REST APIs and backend services in C# on .NET (this is still a hands-on role)

· Build integrations with external systems: HR platforms, asset management tools, data warehouses, messaging systems

· Write and optimise SQL queries, design database schemas, and maintain data integrity

· Establish and uphold engineering standards: code review, testing, CI/CD, conventions

· Work with Azure services day-to-day: Functions, App Service, Service Bus, Blob Storage, Key Vault

· Contribute to hiring, onboarding, and the technical growth of the team

· Language: C# on .NET (primary, and what you’ll write every day)

· Frameworks: ASP.NET Core (Web API), Azure Functions (isolated worker)

· Database: SQL Server, accessed via Entity Framework Core and/or Dapper (you’ll write queries, design schemas, and optimise performance)

· Cloud: Microsoft Azure (Functions, App Service, Service Bus, Blob Storage, Key Vault, AKS)

· Data platform: Microsoft Dataverse (you’ll integrate with it, not build on it)

· Auth: Entra ID (Azure AD), OAuth 2.0

· DevOps: Azure DevOps (CI/CD pipelines), Docker, Azure Container Registry

You don’t need experience with everything here. Strong C# and SQL are the foundation. The Azure-specific skills can be learned on the job.

Requirements:

Must Have

· 7+ years professional software development experience, primarily in C#/.NET, including time leading, mentoring, or coaching other engineers

· People leadership: you’ve coached, mentored, or line-managed developers, and you get satisfaction from making the people around you better, as well as from writing good code yourself

· Software design maturity: you think in terms of domain models, clean architecture, and separation of concerns. We build with strongly typed C#, dependency injection, repository patterns, and domain-driven design. You build scalable, maintainable systems, and you set that standard for the team

· API development: you’ve designed and built REST APIs with ASP.NET Core, understand HTTP, status codes, authentication patterns

· SQL: comfortable writing queries, designing tables, understanding execution plans. You’ve worked with a relational database (SQL Server, PostgreSQL, MySQL) as a core part of your job

· Cloud experience: you’ve deployed and maintained services in production on a cloud platform (Azure, AWS, or GCP). You understand how things like storage, messaging, and secrets management work

· Testing discipline: you write tests for your code (xUnit, NUnit, or similar), care about reliability, and instil the same habits in the team

· Judgement and ownership: you can take a problem, set the approach, build it, and ship it, and you know where to invest effort and where not to

Nice to Have:

· Experience with Microsoft Azure specifically (Functions, App Service, Service Bus)

· Async C# (async/await, Task-based patterns)

· Hands-on experience with Entity Framework Core and/or Dapper

· Docker and container deployment

· Experience with Dataverse, Dynamics 365, or Power Platform

· Experience building integrations with third-party APIs and file-based data exchanges

· Familiarity with infrastructure-as-code (Bicep, ARM templates, Terraform)

· Experience establishing engineering practice (code review culture, CI/CD, standards) in a small or growing team

· Exposure to Python (some of our existing services are written in it)

· A computer science, engineering, or mathematics degree: the grounding in fundamentals it gives tends to show in how people approach hard problems

Not Required:

· Frontend development skills (we have separate frontend capability)

· Specific domain experience in aviation or transport (we’ll teach you)

· Experience with every framework listed: if you know C# and .NET well, you can pick up the rest quickly, Builders. You want to write code that solves real problems. You get satisfaction from seeing something you built running in production and used., * Do you have 7+ years of professional software development experience primarily in C#/.NET?

• Have you people leadership skills and experience?
• Are you able to work from the office (close to Gatwick), Monday to Friday?

Pulled from the full job description

• Free parking
• Company pension
• Casual dress
• UK visa sponsorship
• Transport links
• On-site parking, * Casual dress
• Company pension
• Free parking
• On-site parking
• Transport links
• UK visa sponsorship

Multipliers. You make the people around you better. You review thoughtfully, explain your reasoning, and help others take on work they couldn’t before.

Pragmatism. You know when to engineer something properly and when a simpler approach will do. You don’t over-engineer.

Curiosity. When something breaks, you keep going until you understand the cause. When you encounter a new system or API, you read the docs and experiment. You’re comfortable working in systems you don’t yet know.

Ownership. Your code, your responsibility. When something breaks in production, you want to be the one who can put it right.