Full-Stack Software Engineer specializing in AI Orchestration & Complex Systems.

Giannis Roussos

I build software the way I trained in Special Forces and ICU Nursing — assuming someone's depending on it right now.

Now

What I'm Working On

Based in North Carolina (US Citizen). I build AI-powered clinical tools and FHIR-compliant data systems — the kind that need to work at 3AM when a nurse is relying on them.

Recent

Built a clinical AI agent with a multi-model fallback chain (Gemini/Gemma) — if one model hits a 429 or 503, the next picks up automatically. Sub-2-second response times for acute care scenarios. Then I rebuilt the whole thing in Ruby on Rails over a weekend to compare a stateful architecture against the edge-optimized original.

Approach

I think about software the way I think about patient care — it needs to work for the person using it at 2AM under pressure, not just pass its test suite. Special Forces and ICU nursing trained me to assume things will go wrong and build accordingly. These days I focus on AI orchestration and healthcare interoperability — turning messy clinical requirements into code that holds up when it counts.

Capabilities

⚡ Full-Stack & AI Engineering
Next.js 15, TypeScript, Ruby on Rails, Python, SQL
LLMOps: Multi-model orchestration & automated fallback systems
RAG: Vector database architecture (Supabase pgvector) and semantic search
Three.js, WebGL & interactive experiences
Design systems & component libraries
🎯 System Architecture and Implementation
Resilient Infrastructure: 429/503 error handling & graceful degradation
Cross-Framework Fluency: Re-architected a production Next.js agent to Ruby on Rails in a weekend
Product vision, roadmapping & UX strategy
Go-to-market planning & execution
Stakeholder management & cross-functional leadership
📈 Technical Communication & Stakeholder Management
Digital marketing campaigns & conversion optimization
Sales strategy, pipeline management & client relations
Brand development & story-driven content
🏥 Healthcare Expertise
Clinical workflow optimization & compliance
Healthcare Interoperability: FHIR R4 / HL7 integration and clinical data synthesis
ICU and ER Registered Nurse with a decade of experience

Technology Stack

Core Infrastructure & Systems

TypeScript

Next.js

Node.js

PostgreSQL

Angular

React

AI/LLM

AWS

Tailwind

Three.js

Python

Git

Ruby on Rails

Firebase

DynamoDB

Selected Projects

2023 - 2026

Architecture Case StudyFeatured Project

Aegis AI: Clinical Decision Support

Re-architected from Next.js to Ruby on Rails

I took my production Next.js clinical AI agent and re-architected it as a full Ruby on Rails application — then ran identical clinical scenarios through both to see which architecture holds up better at the bedside.

LLMOpsFHIR R4RAGPostgreSQLXAICI/CD

100%

Success Rate

4.8s

Avg Latency

$0.00007

Total / 10 Runs

View Case Study →GitHub Monorepo

Original

Aegis AI — Next.js 14

Edge-latency optimized. Vercel Edge Functions, Supabase pgvector RAG, streaming AI with sub-2s TTFT.

Next.jsTypeScriptSupabaseVercel

Live Demo →

Re-Architected

Aegis on Rails — Ruby on Rails 7

Stateful persistence. PostgreSQL backend, ActiveJob/Sidekiq workers, server-side AI orchestration with persistent audit trail.

Rails 7RubyPostgreSQLFly.io

Live Demo →

Anima Triage: Clinical Intake & Dashboard

AngularAWS LambdaDynamoDBHL7 FHIRTypeScriptHealthcare

Project Details

Patient triage intake and clinician dashboard built on Angular 18 standalone components, AWS Lambda (TypeScript), and DynamoDB. Submissions are stored as HL7 FHIR R4 Bundles with SNOMED CT and LOINC-coded fields — not flat JSON — so data is immediately consumable by any EHR that speaks HL7 without a transformation layer. Full backend deployed via AWS SAM as IaC; 25 unit tests covering form validation, severity colour mapping, and status advancement logic.

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FHIR Pulse: Clinical Interoperability

HL7 FHIRNode.jsAWSHealthcare

Project Details

An interoperability dashboard that pulls HL7 FHIR R4 data through a Node.js middleware layer and visualizes patient vitals in real time. Custom schema validation and HIPAA-compliant data handling — built for clinical environments where stale or malformed data isn't an option.

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PostHog FHIR Event Bridge

HL7 FHIRTypeScriptNode.jsPostHogLOINCHealthcare

Project Details

TypeScript/Node.js bridge that fetches HL7 FHIR R4 Observation resources from a HAPI test server and forwards them to PostHog as structured analytics events with LOINC-coded schemas. Includes dry-run mode for validation before live dispatch - built because clinical data and product analytics should be able to talk to each other.

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Skinstric: AI Biometric Interface

MediaPipeComputer VisionTypeScriptAI

Project Details

AI-powered capture interface using MediaPipe for real-time 3D biometric landmark detection. The system checks image quality before accepting data — if the capture isn't clean enough, it gets rejected rather than feeding noise to the downstream model.

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Summarist: AI SaaS Architecture

AI OrchestrationNext.jsStripePostgreSQL

Project Details

Full-stack SaaS platform that uses LLMs to generate content summaries. Built with Firebase Auth, a tiered Stripe subscription system, and an API layer designed to handle concurrent users without falling over.

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Enterprise API Governance & Security Sentinel

PythonOpenAPIGitHub ActionsCI/CD

Project Details

Python-based static analysis tool that enforces security rules on OpenAPI 3.0 specs. Plugs into GitHub Actions as a CI/CD gate — if your API spec uses insecure protocols or fails compliance checks, the build stops. Replaced a manual review process with something that catches problems before they ship.

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Interactive 3D Engine

Three.jsWebGLAPI ArchitectureGenerative UI

Project Details

3D visualization built with Three.js and WebGL. Custom shaders tuned to hold 60fps on mobile, with an API layer for generative asset creation — the kind of setup you'd use for interactive product configurators or digital twin rendering.

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Ultraverse: Asset Marketplace

Next.jsWeb3 APIState Management

Project Details

Marketplace built with Next.js, connected to blockchain API endpoints for ownership verification. Focus was on getting the state management right so the UI stays snappy even when browsing large asset collections.

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QuickStay: Booking Logic Engine

TypeScriptAPI DesignSaaS

Project Details

Full-stack booking system built with React and TypeScript. Search filtering, date-range availability logic, and mock-API integrations that simulate real reservation workflows end-to-end.

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Firebase Auth & System Architecture (Netflix)

Firebase AuthFirestoreReact

Project Details

Built to get hands-on with Firebase Auth and Firestore. Protected routing, persistent user sessions, and real-time database sync — modeled after a streaming subscription platform.

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Blinkin: API Integration & SPA Logic

ReactAPI IntegrationState Management

Project Details

SPA focused on clean API consumption patterns. Pulls from the TMDB API with efficient data fetching, custom search filters, and global state management for user watchlists.

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Performance Research (Legacy Portfolio)

Next.jsUX/UIPerformance

Project Details

My initial project in the engineering space, focusing on the fundamentals of the Next.js framework. This served as a research platform for mastering responsive grid layouts and the performance implications of client-side animations.

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