I'm Giannis Roussos, a full-stack software engineer based in Athens, Greece. I design and ship scalable SaaS platforms and AI-integrated systems using TypeScript, React, Next.js, and Node.js. I enjoy building practical, maintainable architectures and collaborating across product and design teams to deliver solid user experiences. I’ve led end-to-end production builds, rebuilt system architectures for reliability and performance, and delivered real-time dashboards and AI-powered integrations while prioritizing security, accessibility, and clean code. I thrive in fast-paced environments and love turning complex requirements into elegant, working solutions.

Giannis Roussos

I'm Giannis Roussos, a full-stack software engineer based in Athens, Greece. I design and ship scalable SaaS platforms and AI-integrated systems using TypeScript, React, Next.js, and Node.js. I enjoy building practical, maintainable architectures and collaborating across product and design teams to deliver solid user experiences. I’ve led end-to-end production builds, rebuilt system architectures for reliability and performance, and delivered real-time dashboards and AI-powered integrations while prioritizing security, accessibility, and clean code. I thrive in fast-paced environments and love turning complex requirements into elegant, working solutions.

Available to hire

I’m Giannis Roussos, a full-stack software engineer based in Athens, Greece. I design and ship scalable SaaS platforms and AI-integrated systems using TypeScript, React, Next.js, and Node.js. I enjoy building practical, maintainable architectures and collaborating across product and design teams to deliver solid user experiences.

I’ve led end-to-end production builds, rebuilt system architectures for reliability and performance, and delivered real-time dashboards and AI-powered integrations while prioritizing security, accessibility, and clean code. I thrive in fast-paced environments and love turning complex requirements into elegant, working solutions.

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Experience Level

Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Intermediate
Intermediate
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Language

English
Fluent
Greek, Modern
Fluent
Spanish; Castilian
Intermediate
German
Intermediate
French
Intermediate

Work Experience

Freelance Software Engineer at Hestia's Hearth LLC
January 2, 2026 - Present
Designed and shipped AI-enabled clinical decision support using Gemini/Gemma architecture, RAG via Supabase pgvector, PubMed grounding, FHIR4 explorer, Redis rate-limiting. Rebuilt Ruby on Rails stack for faster performance (60% faster) and reduced client-side JS payload by 85%. Built FHIR Pulse real-time clinical dashboard with SVG rendering and a Node.js/Express proxy on AWS App Runner, reducing client-side processing overhead via server-side data transformation. Developed Python/OpenAPI 3.0 static analysis tool integrated with GitHub Actions as CI/CD gate for API security compliance.
Software Engineering Intern
January 2, 2026 - February 2, 2026
AI selfie-caption module using MediaPipe BlazeFace for real-time face detection, evolving from pixel-based detection to production-grade 36-segment landmark alignment feedback. Stack: React, Next.js, TypeScript, Firebase, Browser Media AI.
Software Engineer Intern at Summarist
December 1, 2025 - January 1, 2026
Built a full-stack SaaS audiobook platform with manual Stripe API integration, Firebase Auth, Firestore, SSR-optimized content delivery, and Redux-based feature gating; 3.0x performance improvements. Tech stack: React, Next.js, TypeScript, Firebase, Redis, Stripe.
Critical Care and Emergency Registered Nurse (Travel and Staff) at AMN Health Care / Health Trust Workforce Solutions
January 1, 2017 - January 1, 2025
Managed critical care and emergency patient loads across 15+ facilities under high-stress conditions, handling COVID crisis response; frontline nurse with cross-functional collaboration and triage.
District and Regional Sales Manager at InterFACE / DriveTime / DiaGeo / AmeriBank
January 1, 2007 - January 1, 2015
Managed 7 locations (+17% profitability). Launched DriveTime's 100th nationwide location and grew Diego territory market share by 35% through strategic sales leadership and partner development.
Software Engineering Intern at Hestia's Hearth LLC
December 1, 2025 - February 2, 2026
AI selfie-capture module using MediaPipe BlazeFace for real-time face detection, iterating from pixel-based detection to a production-grade 36-segment live-alignment feedback system.
District and Regional Sales Manager at InterFace / DriveTime / Diageo / AmeriBank (as listed on resume)
January 1, 2007 - January 1, 2015
Managed 7 locations (+17% profitability), launched DriveTime's 100th nationwide location, and grew diagnostic territory market share by 35%.

Education

Software Engineering Program at FESI Institute
January 11, 2030 - April 30, 2026
B.S. Nursing at University of West Florida
January 11, 2030 - April 30, 2026
B.S. HR Management at Oakland University
January 11, 2030 - April 30, 2026
Software Engineering Program at FESI Institute
January 11, 2030 - April 30, 2026
B.S. Nursing at University of West Florida
January 11, 2030 - April 30, 2026
B.S. HR Management at Oakland University
January 11, 2030 - April 30, 2026

Qualifications

Registered Nurse
April 30, 2026 - April 30, 2026
ACLS Provider
April 30, 2026 - April 30, 2026

Industry Experience

Software & Internet, Healthcare, Professional Services, Travel & Hospitality, Other, Education
    paper Aegis AI Clinical Decision Support — Multi-Model LLM Orchestration Platform

    Multi-model AI clinical decision support platform built independently in both Next.js and Ruby on Rails to benchmark architectures.

    What it does
    Clinicians paste medical records and receive distilled summaries, suggested differential diagnoses, treatment options, and live evidence from PubMed — all grounded in the document context only, with no external knowledge injection (hallucination eliminated by design).

    Architecture highlights

    • Five-model Gemini/Gemma waterfall cascade (Gemini 2.5 Flash → Flash Lite → three Gemma variants)
    • Reactive 429/503 switching with capability detection between Gemini and Gemma model families (Gemma does not support the systemInstruction field — handled with a runtime supportsSystemInstruction() check)
    • 45-second AbortSignal timeout per call
    • RAG via Supabase pgvector with a pure-TypeScript cosine-similarity fallback path for RPC failures
    • HL7 FHIR R4 data explorer and raw .hl7 file ingestion alongside PDF and text
    • Live PubMed evidence grounding for clinical claims
    • Redis rate limiting, Zod schema validation, structured audit logging

    The Rails benchmark
    Rebuilt the entire system in Ruby on Rails over a single weekend (framework learned from scratch) to compare architectures. Result: 60% faster total execution (5.6s vs 14.7s), 85% reduction in JavaScript payload.

    Stack: TypeScript, Next.js (App Router), Ruby on Rails 7, Supabase (Postgres + pgvector), Vercel AI SDK, Redis, Zod, Hotwire (Turbo/Stimulus), Vercel, Fly.io

    Live demos:

    Source: https://www.twine.net/signin

    paper FHIR Pulse — Real-Time HL7 FHIR R4 Clinical Interoperability Dashboard

    Real-time patient vitals dashboard pulling HL7 FHIR R4 data through a Node.js/Express proxy on AWS App Runner.

    Why it exists
    Built from the perspective of an ICU nurse who saw firsthand how fragmented and slow FHIR data delivery is in production hospital environments. The goal: prove that clean server-side data transformation can deliver a responsive clinical dashboard without overloading the browser.

    Technical highlights

    • Custom SVG waveform rendering for live patient vitals
    • Server-side data transformation reducing client-side processing overhead by 30%
    • Node.js/Express proxy layer running on AWS App Runner
    • Environment-driven configuration for multiple FHIR sandbox sources
    • React/Next.js frontend with responsive design across desktop and tablet form factors

    Stack: TypeScript, Next.js, Node.js, Express, AWS App Runner, HL7 FHIR R4, SVG

    Live demo: https://www.twine.net/signin
    Source: https://www.twine.net/signin

    paper Skinstric — Real-Time Browser-Based Face Capture Module

    AI selfie-capture module built during a paid software engineering internship at Skinstric. Iterated from naive pixel-based detection to a production-grade implementation that ships well beyond the original Figma spec.

    The technical core
    A real-time visual feedback ring of 36 independent arc segments around an oval, each lighting up as the user’s face aligns with it. Built from first principles — no library handles this specific combination of geometry, smoothing, and rendering.

    Implementation details

    • BlazeFace bounding box geometry with mirror correction for the front-facing camera (scaleX(-1) on the video element flips raw coordinates — corrected before segment math runs)
    • Per-segment confidence calculation: angle the segment occupies, find the corresponding point on the oval and on the face bounding-box ellipse, measure normalized distance, convert to confidence
    • Centering score multiplier so segments only fully illuminate when the face is both well-sized and well-centered
    • Asymmetric temporal smoothing (0.4 rising, 0.25 falling) and spatial smoothing across neighboring segments for a fluid 30fps animation
    • Rendered as a conic-gradient built from 36 per-segment RGBA values, masked with a radial gradient so only the 4px border ring shows color
    • Firebase Cloud Storage integration for capture upload and admin dashboard

    Stack: TypeScript, Next.js, React, MediaPipe BlazeFace, Firebase Cloud Storage, Browser Media API, SVG, Conic Gradients

    Live demo: https://www.twine.net/signin
    Source: https://www.twine.net/signin