Senior Software Engineer – Platform Migration

About the Role

We are seeking a highly skilled Senior Software Engineer to lead the migration of our legacy platform, hands-on. The difficulty here is not writing the replacement - it is establishing what the existing system actually does, including the behaviour nobody documented and the edge cases customers have quietly depended on for years. You will be reading a lot of code that was written before most conventions you take for granted existed.

A significant part of our platform still runs on classic ASP and VBScript. We are migrating it to .NET, incrementally and without downtime, while the site continues to trade.

This is a delivery role for someone with a proven track record of migrating live production systems. We are looking for evidence you have done this before and know how it goes wrong.

Responsibilities

• Migrate classic ASP / VBScript applications to C# / .NET, incrementally and with the site live throughout.
• Untangle and modernise legacy data access patterns, including inline SQL and stored procedure logic.
• Build parity and regression testing that gives real confidence a migrated page behaves identically.
• Work with the other streams to sequence migration around their roadmaps, and to hand over migrated areas cleanly.
• Use agentic development tooling such as Claude Code as a core part of how you deliver, with the judgement to know when to rely on it and when not to.

How We Work

Small, focused streams with real ownership. Engineers shape work rather than receive tickets. We deploy frequently and expect people to own what they ship into production. Our stack is C# / .NET and React / Next.js running on on-prem infrastructure alongside managed cloud services.

Experience with classic ASP and VBScript is also desirable - we do not expect it to be what you have been doing recently, and we are not asking you to stay in it, as the objective is to remove it.

We use agentic development tooling heavily, Claude Code and similar and expect you to be fluent with it. We are equally interested in your judgement about it: where it accelerates you, where you deliberately don't use it, and how you review what it produces before it reaches a customer.

To be clear about emphasis: this is a software engineering role first. We are hiring for demonstrated delivery of production systems. AI capability is part of how the work gets done, and sometimes part of what gets built - it is not the qualification.