Senior C# Developer

Senior C# Developer / Senior Software Engineer £70,000 to £80,000 Working pattern: Hybrid. x3 days in Office Location: London A global organisation is hiring a Senior Developer to take hands-on technical ownership inside one of its core platform teams. The platform is cloud-based and carries real weight. Secure digital services for end users, case management tooling, client reporting, and live integrations with payroll and banking providers. It is growing, and they want someone senior enough to shape how it grows rather than just add to it. What you would be running: Significant slices of the platform, yours from first design conversation through to the release note and whatever comes back afterwards.The judgement call on technical debt: what's genuinely holding the platform back, what's cosmetic, and what the team should spend its next quarter on.Larger refactoring and re-architecture work when the answer is that the current shape won't carry where the product is going.The data layer as the platform scales, including the integrations that reach outside it to payroll and banking providers.Whether problems surface on your terms or the user's, through the monitoring, logging and alerting you put around what you build.How releases go out and what happens when one doesn't behave.The engineering standard around you, set through code review, mentoring and the example your own work sets.AI-assisted tooling used with your name still on the output, which they've been deliberate about wanting rather than quietly tolerating. What they need from you: Deep commercial C# and .NET, ideally .NET 8 or later, on a codebase you stayed with long enough to know its history.Ownership of live software: releases you planned, incidents you investigated, production problems you fixed at 6pm on a Friday.Performance work with evidence behind it, across C# and the data layer, using Entity Framework or EF Core against SQL Server and Azure SQL.API and service design that survived contact with real load, built in ASP.NET or ASP.NET Core.Mentoring and code review you have already done, with a view on what makes feedback land rather than just get given.Azure in anger: Functions, WebJobs, Blob Storage, and Application Insights when something needs diagnosing.CI/CD and automated build and deployment as part of how you work, not something a platform team handles for you.Tests you wrote and then had to maintain, which is where most people find out what their testing habits are really worth.Secure development practice, in an environment where the data is sensitive and that is not a formality. Useful but not essential: regulated or financial services environments, involvement in a major refactor or re-platform programme, considered use of AI-assisted development tooling where you still own what ships. What you get back: a certified B Corp, hybrid working, professional study support where it applies, life assurance, income protection, enhanced maternity, paternity, adoption and shared parental leave, and internal Wellbeing, LGBTQ+, Multicultural and Women's networks. One thing worth being clear on: this is a hands-on senior developer role, not a lead or architect role wearing a different title. You would be in the codebase every day. Developers looking for the step where mentoring and design reviews replace delivery are unlikely to be a fit, and so are people who have only ever built greenfield and never had to live with what they shipped. What counts here is whether you have owned significant pieces of a production platform end to end and been the person who fixed it when it broke. Apply today for immediate consideration but please note, they are unable to offer sponsorship at this time.