Senior Principal Software Engineer Job at One Call

Job Description

The Senior/Principal Software Engineer provides architectural depth, delivery excellence, and hands-on leadership in a complex, legacy-heavy environment that’s actively modernizing. This role sits at the center of technical decision-making—driving clarity, unblocking teams, improving engineering practices, and delivering high-quality software across several mission-critical applications. This is not a people-management role, but it is a high-influence technical leadership position. You’ll guide engineers, challenge assumptions, simplify complexity, and make pragmatic tradeoffs that accelerate predictable delivery. Our environment includes substantial .NET, SQL Server, WinForms/Web Forms, and VB.NET footprints alongside more modern .NET Core, REST APIs, Azure DevOps, and JavaScript/TypeScript front-ends. You should be equally comfortable operating in both worlds.

Job Responsibility

Own and drive architecture and design discussions across multiple applications and services
Provide pragmatic, hands-on guidance to teams working across .NET, SQL, and mixed front-end stacks
Evaluate legacy architectures and propose modernization patterns (service boundaries, APIs, refactors, consolidation)
Facilitate technical decision-making with crisp rationales, tradeoff analysis, and clear documentation
Champion engineering excellence: code quality, testing, CI/CD maturity, observability, and maintainability
Unblock teams quickly by diagnosing issues across the entire stack (app, API, data, infrastructure)
Collaborate with Product, QA, Design, and other engineering teams to ensure predictable delivery
Translate complex requirements into executable technical plans, work breakdowns, and sequencing
Identify risks early and recommend options that balance delivery velocity with long-term stability
Contribute high-quality code in .NET (.NET Framework, .NET Core), C#, and VB.NET where necessary
Build and enhance web apps using ASP.NET MVC, Web API, Web Forms, and WinForms
Develop and optimize SQL Server objects (stored procedures, SSIS packages, ETL pipelines, reporting)
Implement robust APIs, REST services, Windows Services, and data-access layers
Work across JavaScript/TypeScript, jQuery, Knockout, Bootstrap, and related UI frameworks
Elevate engineering practices through code reviews, pairing, and informal mentorship
Introduce and promote standards around branching strategy, trunk-based development, and CI/CD pipelines
Improve team problem-solving approaches—debugging, root-cause analysis, instrumentation
Leverage AI-assisted engineering tools (GitHub Copilot, ChatGPT, Azure OpenAI, etc.) to accelerate development, improve code quality, and enhance documentation
Model responsible, high-impact use of AI by using it for pattern detection, refactoring scaffolds, test generation, API documentation, and reducing cognitive load on repetitive work
Help establish norms for AI usage across the team: when to use it, when not to, how to verify output, and how to integrate it safely into delivery pipelines
Build and maintain Azure DevOps pipelines (YAML, MSBuild, MSDeploy)
Integrate automated testing frameworks (MSTest, NUnit, XUnit, Moq)
Work with legacy build systems (Jenkins, Hudson/VSTS)
Support application packaging using MSI, WiX, InstallShield, and ClickOnce
Script and automate workflows using PowerShell and Bash

Requirements

10+ years building enterprise .NET applications in C# (.NET Framework + .NET Core)
Experience modernizing large legacy .NET codebases (service extraction, modularization, domain consolidation)
Familiarity with Azure cloud services, logging, monitoring, and observability patterns
Experience in healthcare, workers’ compensation, claims processing, or regulated industries
Experience with distributed queues, messaging patterns, event-driven architecture
Experience maintaining VB.NET codebases
Deep experience with ASP.NET MVC, Web API, WCF, Web Forms, WinForms
Strong proficiency in SQL Server (T-SQL, performance tuning, SSIS, SSRS)
Strong front-end fundamentals in JavaScript, TypeScript, HTML, CSS/SASS
Familiarity with jQuery, Knockout, and Kendo UI
required Bootstrap experience
Experience with ORMs (Entity Framework, LINQ, Dapper)
Automated testing expertise with MSTest, NUnit, XUnit, Moq
Azure DevOps pipelines, repos, gated builds, YAML
PowerShell and Bash scripting
Ability to diagnose and resolve complex production issues quickly
Ability to work in an environment that aligns with the company's diversity, equity, inclusion and belonging standards
Ability to work both independently and in a team environment
Demonstrate our core values of Think Big, Go Fast, Deliver Awe, Win Together and Care Deeply

What we offer

Remote Work: We are a remote-first company, and almost all positions receive the flexibility of working from home
Generous Time Off: Besides 8 company holidays and 2 personal days every year, all colleagues receive a minimum of 18 days of paid time off
Comprehensive Benefits Package: Including medical, dental, vision, and pet insurance
401(k) matching program
and company-paid life insurance and short and long-term disability coverage
Supportive Services: We offer a Colleague Assistance Program that provides free counseling and financial services, and our One Call Foundation, a non-profit arm of our company, provides colleagues financial assistance during times of unexpected hardships

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Senior Principal Software Engineer

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