Senior Technical Lead, C# / .NET

OSI Digital • Saint Paul, MN

1d • $60,000 - $12,000 • Hybrid

About The Position

We’re looking for a Senior Technical Lead to become the technical owner of The Customer’s point-of-sale codebase, a mature, business-critical system running in stores every day. This is not a rewrite role. The right person improves the code steadily and deliberately while protecting the store floor from regressions. You’ll modernize incrementally, raise the quality bar across the team, and bring forward practical ideas for new capabilities. As a Senior Technical Lead, you’ll go beyond guiding a single team. You’ll own the hardest technical problems in the platform, coordinate technical decisions across onshore and offshore developers, mentor senior engineers, and work directly with The Customer’s stakeholders to turn business goals into realistic technical plans. You’ll still write code, but much of your impact will come from design reviews, technical planning, and making the right calls about risk.

The platform is built in three layers:
POS application. Built in C# on .NET Framework 4.8 and .NET 10, using ASP.NET Core APIs, Windows Workflow Foundation, and SQL Server.
Shared layers. Common, Hosting, the POS business layer, and a workflow engine, spanning netstandard2.0, net48, and net10 components.
User interfaces. Built in Angular 21.2 and TypeScript 5.9.

Requirements

• Deep expertise in C# and .NET Framework 4.x
• Hands-on experience migrating to .NET 6/8/10, including multi-targeting, netstandard2.0, and resolving package conflicts
• Strong WCF skills: reading bindings, configurations, and contracts, and debugging services
• SQL Server and ADO.NET, including comfort reading stored procedures and working with DataSets
• MSBuild, NuGet, and PowerShell build scripting, with Azure DevOps pipelines
• A proven track record of shipping safely to production
• Clear written communication with onshore and offshore teams and directly with client stakeholders
• Willingness to be onsite with The Customer in Richfield, MN as needed

Nice To Haves

• Windows Workflow Foundation 4 (XAML)
• Retail POS or payments experience: EMV, tender, store-and-forward, and PCI DSS awareness
• Enough Angular to read and understand client-side code
• CoreWCF, ASP.NET Core, and OpenID Connect authentication
• Checkmarx remediation, TeamCity, and similar tooling

Responsibilities

• Own the technical direction of the POS codebase and be accountable for its health, stability, and evolution
• Lead incremental modernization from .NET Framework toward modern .NET without a big-bang rewrite
• Protect production by reviewing changes for risk, anticipating how things can break, and ensuring safe releases
• Coordinate technical decisions across onshore and offshore developers so work stays consistent and aligned
• Mentor senior engineers and set engineering standards for code, documentation, and process
• Work directly with The Customer, including onsite visits, to understand needs, push back on unrealistic designs or timelines, and propose improvements
• Leave the code, documentation, and processes in better shape than you found them

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed