Role Overview We're building a greenfield web platform that delivers modern, cloud-based experiences aligned with Sensei Cloud. The application is modular in nature and will grow over time. As a Full-Stack Engineer with a backend focus, you will be a core contributor shaping the Rails API, data layer, and Azure platform integrations from the ground up — while remaining capable of working across the entire stack when needed. Your primary ownership area is the backend: data modeling, API design, data mapping across dental practice management systems (DPMS), external healthcare system integrations, and background processing. You will interact with Azure Cosmos DB for DPMS data and leverage Azure PostgreSQL Hyperscale (Citus) to host application data at scale. You will also contribute to frontend work as the team and product evolve. This is a full-product ownership role in a HIPAA-regulated healthcare environment, requiring strong technical judgment, attention to compliance, and close collaboration with your fellow engineers and product stakeholders. You will work within a Human -> AI -> Human engineering workflow, using AI tools to accelerate delivery while maintaining full accountability for correctness, security, and compliance. Key Responsibilities Frontend Design, build, and maintain React components for a dental practice scheduling application Implement responsive, mobile-first layouts using Tailwind CSS and standard breakpoints (sm, md, lg) Integrate frontend features with a Rails-based API using Axios and TanStack Query for data fetching, caching, and mutations Implement Azure AD B2C authentication using MSAL, including protected routes, token acquisition, and Axios interceptors Maintain clean, readable TypeScript code that conforms to ESLint and Prettier standards Backend Design, build, and maintain Rails API endpoints (API-only mode) serving dental scheduling, patient, and practice data to the React frontend Model and evolve PostgreSQL schemas using ActiveRecord migrations with an emphasis on clarity, performance, and data integrity Build and operate background jobs using Sidekiq and Redis for asynchronous and long-running tasks Write and maintain RSpec test suites using FactoryBot, WebMock, and VCR for external HTTP integration testing Run and remediate findings from Brakeman and bundler-audit as part of normal development workflows Shared Collaborate closely with fellow engineers and product stakeholders throughout feature development Participate in AI-augmented development workflows, reviewing and validating AI-generated code against acceptance criteria Follow Git best practices: feature branches, pull requests for all changes, and conventional commit messages Proactively update documentation when behavior or architecture changes Requirements Core Technical Skills Strong experience with TypeScript and React, including functional components and custom hooks Experience consuming REST APIs using Axios, including authentication header injection Proven ability to build responsive UIs using a utility-first CSS framework (Tailwind or similar) Experience with server-state management libraries such as React Query, SWR, or RTK Query Strong experience with Ruby on Rails in API-only mode, including ActiveRecord, migrations, routing, and middleware Solid PostgreSQL knowledge, including schema design, query performance awareness, and migration safety; hands-on experience with Sidekiq or equivalent for background job processing Familiarity with Git-based workflows, including pull requests and conventional commits Comfortable reading and maintaining Markdown documentation Proven testing discipline across both frontend (React Testing Library, Playwright) and backend (RSpec, FactoryBot, WebMock/VCR) AI-Augmented Development (Required) Hands-on experience using AI coding assistants (e.g., Claude Code, GitHub Copilot, Cursor) as part of daily development Clear understanding of the Human -> AI -> Human review loop, with human ownership of all decisions Ability to maintain supporting documentation such as READMEs, architecture notes, and AI configuration files (e.g., CLAUDE.md) Awareness of AI traceability practices, including commit trailers, review checklists, and prompt hygiene HIPAA & Compliance Awareness (Required) Strong understanding that Protected Health Information (PHI) must never appear in code, tests, logs, commits, or error messages Comfort working exclusively with synthetic or mock data (e.g., SYNTHETIC_-prefixed data) Awareness of secure coding practices, including no hardcoded credentials, no PHI in browser storage, and structured logging Availability & Engagement (Required) Minimum 7–8 hours of daily overlap with US East Coast business hours (9 AM–5 PM ET) Punctual, consistent attendance at daily standups and scheduled team ceremonies Same-day turnaround on code review feedback during working hours Proactive communication when availability changes — before stepping away, not after returning Visible, consistent engagement during working hours as the primary measure of contribution — not evening or weekend catch-up Technologies & Tools Frontend Language: TypeScript 5 Framework: React 19 (functional components, hooks) Build Tooling: Vite 7 Styling: Tailwind CSS 4, clsx, tailwind-merge (cn() helper) Server State: TanStack Query (React Query) v5 Routing: React Router v7 HTTP Client: Axios (with authentication interceptors) Authentication: Azure AD B2C via MSAL Code Quality: ESLint 9, Prettier 3 Backend Framework: Ruby on Rails 8.1 (API-only mode) Database: PostgreSQL 16 Background Jobs: Sidekiq with Redis 7 Testing: RSpec, FactoryBot, WebMock, VCR Serialization: JBuilder HTTP Client: Typhoeus (or Faraday) for external service integrations Authentication: Azure AD B2C JWT validation via JWKS (custom middleware) Security Scanning: Brakeman, bundler-audit Linting: RuboCop, rubocop-rails, rubocop-performance Shared Development Environment: Docker Compose Version Control: Git with feature bran