Senior Technical Lead, C# / .NET

OSI Digital, Inc.; Saint Paul (MN); On-site; USD 120,000 - 150,000; Full time

Job summary

OSI Digital, Inc. is seeking a Senior Technical Lead to own the POS codebase, drive incremental modernization, and mentor engineers in a hybrid Greater Minneapolis/St. Paul setting. You’ll collaborate with stakeholders, ensure system health, and balance risk with practical delivery.

In this role, you’ll guide architectural decisions across onshore and offshore teams, write impactful code, and help shape the platform’s future while maintaining stability in production environments.

Qualifications

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

Responsibilities

• Own the technical direction of the POS codebase and ensure 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 and safe releases.
• Coordinate technical decisions across onshore and offshore developers for consistency.
• Mentor senior engineers and set engineering standards for code, documentation, and process.
• Work directly with The Customer, including onsite visits, to understand needs and propose improvements.
• Leave the code, documentation, and processes in better shape than you found them.

Skills

C# / .NET

WCF

SQL Server

Azure DevOps

MSBuild

PowerShell

Communication

Tools

Azure DevOps pipelines

MSBuild

PowerShell scripting

Job description

Role: Senior Technical Lead, C# / .NET
Location: Greater Minneapolis/St. Paul, Minnesota Hybrid
Type: Full Time

About the role

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 system

The platform is built in three layers:

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

What you’ll do

• 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

Must have

• 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 have

• 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

Who you are

• A clear, proactive communicator who’s looking for a long-term role where youi can grow with the platform and the team
• You’ve modernized a .NET Framework system incrementally, not through a big-bang rewrite
• You ask the right questions and think carefully about how changes can break things
• You care about leaving systems better than you found them, from code to documentation to process
• You’re comfortable owning outcomes and being the person others rely on for technical judgment