Senior Fullstack Engineer, Replay

Here's what makes this role different: you're not just a .NET engineer who "also knows AI." We want someone who has already figured out that tools like Cursor, Claude Code, and Codex aren't toys - they're force multipliers. You'll use AI agents every day to tear through migrations, refactors, and test coverage that would take a traditional team weeks. But you also know when the AI is wrong, when to step in, and how to keep quality high. Think of it as having a junior engineer with infinite energy and zero judgment - your job is to supply the judgment.

ESSENTIAL JOB RESPONSIBILITIES & KEY PERFORMANCE OUTCOMES

Ship modernization work at a pace that surprises people

This is your superpower. You'll: 

• Use AI agents (Cursor, Claude Code, Codex) to blow through framework upgrades, refactors, API extraction, test scaffolding, and documentation - while catching hallucinations and preventing regressions before they hit a PR. 

• Build reusable playbooks the team can actually follow: prompt templates, repo-level agent instructions, migration checklists, review heuristics, and clear "definition of done" standards for AI-assisted changes. 

What success looks like: 

• You measurably move the needle - more modules migrated per sprint, faster PR turnarounds - without a spike in production bugs. 

• The team gets better because of you: PRs are clearer, test coverage grows, documentation stays current, and the same mistakes stop repeating. 

Modernize a real .NET + SQL Server stack into something you'd be proud of 

You'll: 

• Upgrade legacy services to current .NET (LTS where it makes sense), untangling architecture boundaries and fixing the performance issues that have been "known" for years. 

• Push toward a proper API-layer architecture - RESTful, versioned - built for correctness and maintainability, not just "it works." 

• Get your hands dirty with SQL Server: query performance, indexing, transactional correctness. If there are data pipeline needs (Kafka, etc.), you'll help build those too. 

What success looks like: 

• Legacy surface area shrinks sprint over sprint. Critical paths live in modern code. Fewer "oh, that's still in the old system" conversations. 

• APIs get faster and more reliable. Database hot spots stop waking people up at night. 

Own it like it's yours - especially because this is healthcare 

You'll: 

• Build with security and privacy as defaults, not afterthoughts. Least privilege, safe data handling, the works. This is healthcare - getting it wrong isn't an option. 

• Put real quality guardrails in place: automated tests that actually catch things, CI that blocks bad changes, structured logging, observability that tells you what's happening before users do. 

• Review code thoughtfully, have honest architectural conversations, and raise the bar without being a jerk about it. 

What success looks like: 

• Fewer severity-1 incidents. When something does go wrong, root cause takes hours, not days. 

• Automated test coverage grows meaningfully on modernized code. The team stops relying on "just test it manually." 

Work with real humans to ship things that matter 

You'll: 

• Partner with analysts, stakeholders, and other engineers to turn business problems into working software - not just technically correct software, but software that actually solves the problem. 

• Help build delivery plans that are honest about trade-offs. "Right" vs. "right now" is a real tension - you'll help the team navigate it with pragmatic milestones. 

What success looks like: 

• Delivery is predictable. Customer onboarding milestones are met. Features ship with confidence, not crossed fingers. 

REQUIRED SKILLS & EXPERIENCE

• 5+ years building and shipping production systems. Not side projects - real software with real users solving skills; able to work independently and collaboratively in fastmoving teams 

• Some C# and modern .NET experience (Core and beyond). Especially in large codebases and you've done meaningful refactoring and migration work, not just greenfield. 

• Strong SQL Server chops - schema design, query tuning, performance troubleshooting. You've worked on data-heavy applications where the database wasn't an afterthought. 

• Cloud experience with Azure and/or AWS. Azure is particularly relevant here. 

• API design experience - you've built and maintained service-oriented architectures with real versioning, auth, reliability, and testing practices. 

• You actually use AI coding tools as a daily driver. Cursor, Claude Code, Codex, or similar - and not just for autocomplete. You've used agents for multi-file refactors, migrations, test generation, and review workflows. You have opinions about what works and what doesn't. 

• You communicate clearly. Good PR descriptions, straightforward design docs, pragmatic collaboration, low ego. We don't need a rockstar - we need someone the team trusts. 

PREFERRED QUALIFICATIONS

• You've actually done a legacy ASP.NET / .NET Framework modernization before. You know where the bodies are buried and you have the scars to prove it. Bonus points for Azure modernization patterns. 

• Experience with distributed systems tooling - Kafka, event-driven architectures, or working with Postgres alongside SQL Server. 

• Front-end experience with Angular and/or React/Next.js. 

• You've helped establish agent-friendly engineering practices: writing repo instructions that AI tools can follow, breaking work into agent-sized tasks, setting up CI guardrails for AI-generated code, feature flags, canary deployments - any part of the progressive delivery toolkit. 

• Background in regulated domains (healthcare, fintech, payments) where "move fast and break things" will get you fired.