Senior Software Engineer (Principal / Lead Architect)
Come, Innovate, Build, Disrupt & Thrive!
Position Overview
KēSTA I.T. is seeking a hands-on Senior Software Engineer to own the architecture and technical direction of a cloud communications product suite and lead its modernization to .NET 10.
This is a fully remote role reporting directly to the CEO. The engineer will set architecture across the backend services and the Angular and Blazor front ends, decide what gets built and how it is layered, and lead the move from .NET Framework WebForms to modern ASP.NET Core and from .NET 8 to .NET 10, including the incremental split of a monolithic solution into NuGet-connected repositories.
Alongside modernization, the role designs and builds new product capabilities end-to-end, including a partner-facing REST API with OAuth and an MCP server, a voice-agent host using the OpenAI Realtime API, and distributor marketplace integrations. Much of the code is written with AI assistance (Claude Code, Codex or similar), so the role directs those tools, reviews their output, and relies on strong engineering fundamentals.
The engineer will work with a team of 5-7 engineers, including offshore engineers in Spain who direct their own work, and will review every pull request, mentor those engineers, and set engineering standards. There is no dedicated QA team, so testing is part of the work and will leverage AI (secondarily).
Success means a sound architecture, a well-led modernization, a raised quality bar, and a team that increasingly shares design judgment. Communication and accountability are essential, as this person will help shape the company's future direction.
The preferred engagement model is contract-to-hire, with direct hire also possible.
Key Responsibilities
•Set and maintain the architecture across the backend services and the Angular and Blazor front ends, deciding what gets built, how it is layered, and what is left untouched.•Own technical direction, including the .NET 10 migration (WebForms to ASP.NET Core, .NET 8 to .NET 10) and the incremental split of the monolithic solution into NuGet-connected repositories. Review the current plan, adjust it where warranted, and lead its execution.
•Design and build new product capabilities end to end, such as a partner-facing REST API with OAuth and an MCP server, a voice-agent host using the OpenAI Realtime API, distributor marketplace integrations, and a service-pack upgrade orchestrator.
•Review every pull request, whether written by a person or a model, and own the engineering rules: readable over clever, additive over invasive, partner contracts never broken without a decision, and tests that fail when behavior is wrong.
•Lead the AI-assisted engineering practice, including agent context docs, skills, review workflow, and judgment on where model output can be trusted.
•Mentor and unblock the offshore engineers, helping them build design judgment so less of the design depends on one person.
•Hold the quality bar with the team through unit tests in the pipeline, live integration tests against a sandbox, and Playwright browser tests, deciding what is tested at which layer.
•Onboard vendor changes outside the team's control, including 3CX service packs (decompile, re-map, test, roll out) and PSA and CRM API changes.
•Write the durable record: ADRs, PR descriptions that explain the reasoning, and runbooks the support team can follow without an engineer.
•Administer the GitHub and Azure DevOps organizations, including repositories, branch protection, access, service connections, deploy keys, personal access tokens and expiry, agent pools, variable groups and Key Vault links, GitHub Apps that run AI review, and the GitHub to Azure DevOps connection.
•Maintain an inventory of the vendor accounts engineering depends on (Azure subscription, Datadog, NuGet feed, AI tooling seats) so nothing expires unnoticed.
•Cover CI/CD pipelines as needed, working alongside the DevOps manager who owns them day to day.•Act as a light, shared second-line escalation for production regressions caused by shipped code, without a pager rotation.
Required Qualifications
•10+ years building and running production software in C# and .NET, including years of owning a system in production, not only delivering features into one.
•Experience designing the architecture of a multi-service system and living with the consequences.
•Fluency in both .NET Framework (ASP.NET WebForms or MVC, EF6 or ADO.NET) and modern ASP.NET Core (.NET 8/10, EF Core, minimal APIs or controllers, DI, hosted services), with at least one real application migrated from the former to the latter.
•Full stack development experience across backend and front end, with C# on .NET 10 as the core requirement.
•Deep relational database skill across SQL Server, MySQL, and PostgreSQL, including schema design, hand-written DDL, query tuning, and understanding what the ORM is doing underneath.
•Experience designing and versioning REST APIs with external consumers who cannot be broken.
•Comfort on Linux (systemd, nginx, SSH, reading logs) and Windows (IIS, SQL Server).
•Experience administering a GitHub organization and an Azure DevOps organization for a team, including access control, branch protection, service connections, agent pools, and PAT and secret hygiene.
•Ability to read, change, and debug YAML pipelines and to cover pipeline ownership, though not as the day-to-day owner.
•1 to 2 years of daily use of agentic coding tools (Claude Code, Codex or similar), with a clear track record before them and the ability to direct these tools and catch their errors.
•Experience leading code review for a team: setting standards, giving reasons, and holding the line without friction.
•Experience writing automated tests as part of the work, including unit tests, integration tests against a real environment, and browser tests, with Playwright familiarity expected.•Ability to work independently and fully remote, write clearly, and explain technical trade-offs to a CEO in plain language.
•Docker experience, as the environment is Docker-based.
•Employment sponsorship is not available for this role.
Preferred Qualifications
•Angular (TypeScript) and Blazor
•Proxmox or any KVM hypervisor, Redis, Docker, S3-compatible storage, Azure Key Vault
•Experience building MCP servers or LLM-integrated features, and writing agent skills
•Telephony experience (3CX, SIP, VoIP); training is provided
•Managed service provider industry experience, or PSA tools such as ConnectWise•Experience working with contributors in other time zones
Work Environment & Physical Requirements
•Fully remote; work is performed off-site with no on-site requirements.
•Collaboration with offshore engineers based in Spain, working across time zones.
Available Benefits
•Medical Benefits (Platinum level plans available)
•Work from home / Hybrid / Onsite options
•PTO
•Holiday Pay
•VTO
•401K
•Charitable Match
•Training reimbursement
About KēSTA I.T.
Our name says it all; KēSTA I.T. (Keys-to-I.T.) AND our people are our keys to our success!
KēSTA I.T. is a premier Utah-based technical staffing and consulting services firm. We specialize in temporary and permanent placement of Software, Hardware, Network, Cloud, CRM/ERP, Data, End-User support, Web and Executive / leadership-based positions on a full time and consulting basis.
If you're interested in a role where top performance is rewarded, personal time is valued, and excellence is demanded at every level we want to talk to you today!
Where do you want to go? We've got the keys! ~
KēSTA I.T.