Senior Full Stack Engineer (Backend Focus) - 18371

Employment Type: Full time, independent contractor (​​Short Term Contract)
Work Model: Remote
Work Hours: US work hours 

We are seeking a strong, senior Full-Stack Engineer to build a production-ready application that uses LLM vision models to extract structured data from images and transform it into validated outputs for healthcare billing workflows.

This role is backend-dominant but fully full-stack. You will implement a multi-stage data extraction and validation pipeline in Python, integrate it with an existing React frontend, and deploy the system on Google Cloud Platform.

The project has already been extensively scoped. Over 130+ pages of architectural documentation, technical decision documents, and validation rules are available. Your primary focus will be implementation, integration, testing, and production hardening, rather than early product discovery.

You will work directly with the founder to transform the detailed specification into a reliable production application.

The platform extracts billing data from hospital census sheets used by physicians.

Doctors photograph their patient lists, and the system:

• Validates image quality on-device
• Extracts structured data using LLM vision models
• Runs a multi-stage backend validation pipeline
• Allows physicians to review extracted data
• Exports validated records to billing software

The goal is to eliminate hours of manual transcription work physicians perform each week.

Mobile App: React + Capacitor
Backend: Python + FastAPI
Infrastructure: Google Cloud Run
Database: PostgreSQL or Firestore
LLM Vision: Claude (primary) with backup provider
CI/CD: GitHub Actions
Compliance: PHIPA healthcare privacy requirements with Canadian data residency

This project centers around a data extraction and validation pipeline, not a traditional CRUD application.

• Integrate LLM vision models to extract structured data from uploaded images
• Implement failover logic between primary and backup model providers
• Normalize and parse model outputs into structured backend objects

Build a multi-step validation system including:

• Billing code normalization and database validation
• Diagnostic code resolution
• Date format disambiguation
• Physician lookup and reference dataset matching
• Data confidence scoring

Extracted data must be categorized into:

• High-confidence
• Review-required
• Invalid

before export.

• Build backend APIs using Python and FastAPI
• Design secure data pipelines and database schemas
• Implement validation and processing workflows
• Configure CI/CD pipelines and cloud infrastructure

• Review and integrate an existing React + Capacitor frontend
• Connect backend APIs to the mobile UI
• Implement state management, validation states, and error handling
• Ensure mobile-grade reliability and resilience

• Generate spreadsheet outputs compatible with billing software
• Implement multi-layer validation gates before export
• Prevent invalid data submissions through deterministic checks

• →Implement a production-ready full-stack system from detailed specifications
• →Build backend services using Python and FastAPI
• →Integrate and validate a React + Capacitor frontend
• →Deploy and manage infrastructure on Google Cloud Platform
• →Implement CI/CD pipelines and secure DevOps practices
• →Build reliable data extraction and validation pipelines
• →Integrate LLM APIs with redundancy and failover logic
• →Write automated tests and maintain high code quality
• →Ensure system monitoring, reliability, and error handling
• →Proactively improve engineering solutions where needed

• Strong, senior-level full-stack engineering experience
• Deep expertise with Python backend development
• Proven experience building and shipping production-grade applications end-to-end
• Experience building production systems using FastAPI or similar frameworks
• Experience working with React applications
• Hands-on experience deploying and managing systems on Google Cloud Platform (GCP)
• Experience building data processing pipelines or validation systems
• Experience integrating third-party APIs
• Strong debugging, troubleshooting, and problem-solving ability
• Experience contributing to or shipping a mobile application (React + Capacitor or similar preferred)

• Comfortable working independently from detailed technical specifications
• Strong written communication and documentation skills
• Ability to own complex systems end-to-end

• Experience working with LLM APIs or AI-driven applications
• Experience with OCR or image processing workflows
• Familiarity with PostgreSQL or vector databases
• Experience with DevOps workflows and CI/CD
• Experience building mobile-friendly web applications
• Experience working with healthcare or regulated data environments

The ideal engineer for this role:

• Works independently without needing heavy management
• Is comfortable reading and implementing detailed technical documentation
• Has strong problem-solving and debugging ability
• Communicates clearly and flags issues early
• Enjoys owning systems end-to-end
• Thrives in implementation-focused engineering work

Engineers who enjoy building complex systems from detailed specifications will excel in this role.