Senior .NET Engineer | VB.NET + C# + SQL Server Modernization

Nice to meet you. We are United Hub Digital, a nearshore technology consultancy focused on data, analytics, software products and applied AI for global organizations. We work with lean teams and a high level of technical autonomy.

The Project

We are modernizing a line-of-business platform for a US client: a legacy VB.NET and SQL Server application that keeps running while new C# code grows alongside it. Documentation is thin, and many rules live only in the code and the data, so much of the work is finding out what the system actually does, and whether that is correct, before changing it. You will work alongside a tech lead and directly with the client's IT and operations teams.

The role is mostly hands-on engineering: reading legacy code, maintaining and extending the VB.NET application, writing new C# and SQL, testing, documenting. It also has a consulting side: joining client meetings, explaining technical decisions to the client's IT team and operations staff, and presenting options so the client can decide with confidence.

What You Will Do

• Own tickets end to end: understand the problem, find the real rule in the legacy code and the data, implement, test, document, and explain the result to the client.
• Maintain and extend the legacy VB.NET application and its stored procedures, and write new C# and SQL with tests. New features land in VB.NET when they belong there.
• Reverse engineer business rules nobody wrote down: read the code, query the databases, measure against real production files, and write down what is actually true.
• Use AI every day, Claude Code in particular, across discovery, planning and implementation, and verify what it produces before you rely on it.
• Join client meetings in English: present findings, propose options, answer questions, and bring the conversation back to the decision when it drifts. Prepare short presentations and written proposals that explain why one approach is better than another in words the client's IT and operations staff can follow.
• Write clear Jira tickets, pull request descriptions and comments, keep the living documentation current, and raise what you find as you go: defects, risks, data corruption, opportunities to simplify, even when nobody asked.

What You Need to Have

Depth in C#, VB.NET, and SQL Server matters more than breadth.

• English proficiency. Must be able to lead meetings in English.
• Real, recent experience working directly with US or other foreign clients, in English, as the only shared language. We are looking for someone who has run technical meetings with non-technical stakeholders, explained a problem more than one way until it landed, stayed calm and factual when challenged, and followed up in writing.
• The second non-negotiable requirement is depth in C#, VB.NET, and SQL Server. This means having read and changed large VB.NET modules without breaking what is around them, written current C# (.NET 8 or later) with automated tests, and worked T-SQL at the level of stored procedures, cross-database queries, and query plans.

The other requirements:

• Entity Framework Core, xUnit and test-first development, including tests that pin a legacy behavior before you change it.
• Git and pull requests in a team: small focused commits, one ticket per commit, review discipline. We use Azure DevOps Server and Jira.
• AI-assisted development as a daily practice, with Claude Code or a similar assistant, and the habit of reviewing and testing what it produces.
• A track record of running work independently: taking a problem from a vague request to a verified, documented change without waiting for a specification.
• Consulting profile: proactive, asks the right questions, anticipates risks, and communicates trade-offs clearly to technical and non-technical audiences. Keeps proposing and helping when the first answer is no.
• SQL Server Always Encrypted, SSRS or RDL reports, Component One, Word and Excel interop, and Clean Architecture or DDD applied to a legacy modernization are relevant differentiators.

Technical Environment

VB.NET and C# (.NET Framework 4.8 and .NET 10), Windows Forms, SQL Server (T-SQL, Always Encrypted), Entity Framework Core, xUnit, Azure DevOps Server, Jira, Claude Code (Anthropic).

Format

• 100% remote.
• PJ.