Day Shift Mern Stack Developer Jobs in Wisconsin

Position: Full Stack Engineer
Location: Brookfield, Wisconsin

Duration: Contract to Hire
About the role

We are looking for a Full Stack Engineer who can ship features end-to-end across the platform without waiting for someone else to fill in the gaps. You will pick up work that touches the frontend, backend, database layer, and sometimes the infrastructure underneath it all. You will write code that goes into production, and you will be expected to do that at a pace that only works when AI tooling is part of how you think rather than a thing you reach for occasionally.

The platform is a HIPAA-compliant, cloud-native EHR built FHIR-native from the start. The stack is TypeScript end-to-end, runs on AWS, and is designed for AI-assisted development from the inside out. Hono on Lambda for the serverless backend. React 19 with Vite for the SPA. Drizzle for the ORM. tRPC paired with REST and FHIR for the API layer. Every choice in the stack is meant to get the most out of AI code generation, and the team ships at a pace that is only possible when the first draft of code coming out of Claude or Cursor actually compiles and runs.

You will work closely with the Lead Product Architect and the rest of the engineering team. The architecture is set. Your job is to extend it cleanly, write code that fits the patterns already in the codebase, and push back when something does not feel right rather than silently working around it.

What you will own

Feature delivery. You take user stories from ready to shipped. You write the backend handlers, database queries, React components, and integration tests that prove the feature works. You don't hand off the frontend to someone else after the backend is done, and you don't stop at the API boundary. End-to-end is what this seat means.

Code quality inside the patterns. The codebase has patterns. You learn them in your first two weeks, write code that fits them, and flag cases where the pattern is wrong before adding to the mess. We would rather pause for a quick discussion than ship one more layer of cruft on top of something that already needs to be rethought.

AI-driven development. You use Claude and Cursor every day, and you have opinions about how to get the most out of them. You write prompts that produce code you actually trust. You know when to take what the model gives you and when to throw it out and write it yourself. You can pair with a model the same way you would pair with another engineer, including knowing when to disagree.

Code review and pairing. You review your teammates code, leave specific feedback, and accept the same when it comes back at you. You pair on hard problems when pairing is the fastest path, and you write your own code the rest of the time.

Production readiness. Your work goes into production. You write the tests, you check the logs, and you stay close enough to the deploy to know if something you shipped is misbehaving. You participate in the on-call rotation. When something you wrote breaks at 2 AM, you show up.

Compliance discipline. HIPAA is not a checklist you forget once the audit is done. You handle PHI carefully in logs, in non-production environments, and in support workflows. You read the security ADRs, and you ask questions when you are not sure where the line is.

Other duties as assigned. This is an early-stage company, and the role will flex as the business grows. Roles shift, scope moves, you go where the work is.

Requirements

• Full-stack web development. At least five years of production experience building web applications end to end. You have shipped real products to real users, not just personal projects or proofs of concept. You can speak to specific systems you built, what they did, and what you carried forward into the next one.
• AI-assisted development. At least two years of daily work with Claude or an equivalent coding assistant. You are an AI code-first developer, which means the model is part of your loop on every meaningful piece of code, not a tool you turn to when you are stuck. You can show how your workflow has changed over the last two years and where you have landed on what works.
• TypeScript and Node.js. Production experience writing TypeScript. You can hold a conversation about generics, inference, and type design without reaching for a search engine, and you understand how Node.js behaves under load. The codebase is TypeScript end to end, and you will be writing it every day.
• React. Modern React with real production experience. You understand state-management trade-offs, the runtime cost of your choices, and the difference between code that works and code that scales. React 19 with Vite is the current stack, and you should be comfortable with it within a week.
• PostgreSQL. You have written real SQL against PostgreSQL in production, debugged slow queries, and worked with schema migrations without breaking things. Drizzle ORM is the current data access layer, but underneath it is PostgreSQL, and SQL fluency matters more than the ORM.
• AWS exposure. Working knowledge of the AWS surface the platform uses. Lambda, API Gateway, RDS or Aurora, S3, and CloudWatch at a minimum. You may not have made the architectural calls on these services, but you have shipped into them, and you know how to debug what you ship.
• API design. You can build REST and FHIR-style endpoints that hold up under real client load. You understand resource modeling, idempotency, versioning, and authentication. You have read enough HTTP to know what the verbs actually mean.
• HIPAA awareness. Either prior experience shipping in HIPAA environments, or willingness to come up to speed quickly. You will be working with PHI from day one, and the team cannot slow down to explain why a quick fix that puts PHI into a log file is not actually a quick fix.
• English proficiency. You communicate clearly in written and spoken English. Native fluency is not required, but you can hold a video meeting, write a Slack thread, leave a useful code review comment, and ask a clarifying question without translation friction slowing the conversation. The team works across time zones, and most communication is asynchronous and written.
• Education. A four-year college degree from an accredited institution, or demonstrated engineering depth that makes a degree unnecessary. Show the work.

Preferred

• EHR or healthcare experience. Prior work on an EMR, EHR, or system that integrates with one. Bonus if you have shipped in post-acute, skilled nursing, or assisted living.
• FHIR R4. Hands-on experience with FHIR R4 resources, bundles, and search parameters. Bonus if you have built a FHIR native system rather than a FHIR facade over a legacy schema.
• Modern TypeScript stack. Production work with Hono, tRPC, Drizzle ORM, or comparable modern TypeScript tooling. We can ramp up on the specific tools, but prior fluency accelerates everything.
• Infrastructure as code. AWS CDK in TypeScript is what we use. Terraform, Pulumi, or comparable production experience translates.
• Multi-tenant SaaS. Production experience with PostgreSQL row-level security, pgPolicy, or comparable tenant isolation patterns. Healthcare multi-tenancy is a stronger signal still.
• Testing depth. Vitest, Playwright, fast check, Testcontainers, or comparable tooling at each layer of the testing pyramid. You know how to write tests fast enough that the team actually runs them.
• Observability. OpenTelemetry, Sentry, Pino, or comparable structured logging and tracing tools inside a serverless system.
• Open source contributions. Visible work in public repositories, especially in the TypeScript ecosystem.