David Lynn - Senior Full Stack Engineer

Q: Where is David based?

David is based in Hallein, Austria .

Q: What languages does David speak?

David speaks the following languages: Chinese (Native), English (Advanced), German (Intermediate) .

Q: How many years of experience does David have?

David has at least 8 years of experience. During this time, David has worked in at least 4 different roles and for 5 different companies . The average length of individual experience is 2 years and 6 months . Note that David may not have shared all experience and actually has more experience.

Q: What is David's latest experience?

David's most recent position is Senior Full Stack Engineer at Fractual .

Q: What companies has David worked for in recent years?

In recent years, David has worked for Fractual , Porsche Informatik GmbH , and Toptal .

Q: Which industries is David most experienced in?

David is most experienced in industries like Transportation , Information Technology , and Retail . David also has some experience in Automotive , Healthcare , and Professional Services .

Q: Which business areas is David most experienced in?

David is most experienced in business areas like Information Technology , Product Development , and Project Management . David also has some experience in Supply Chain Management , Logistics , and Operations .

Q: Which industries has David worked in recently?

David has recently worked in industries like Transportation , Retail , and Automotive .

Q: Which business areas has David worked in recently?

David has recently worked in business areas like Information Technology , Product Development , and Project Management .

Recommended expert

Hallein, Austria

Experience

Apr 2024 - Aug 2025

1 year 5 months

Greece

Senior Full Stack Engineer

Fractual

Built and maintained a full-featured React Native mobile app and companion web portal supporting multi-role access and real-time collaboration for service teams.
Developed a robust NestJS backend using TypeScript, adhering to scalable microservices patterns to support a dynamic task management system.
Designed and optimized PostgreSQL schemas, using advanced indexing and normalized data models to support patient tracking, tasks, and outcome reporting.
Integrated Socket.IO to support real-time team communication, task status updates, and instant notifications across mobile and web platforms.
Developed secure authentication workflows using AWS Cognito, including multi-role login, token refresh, and session timeout handling.
Leveraged AWS S3 for secure document uploads (patient records, resource materials) with signed URLs and access control policies.
Connected AWS SNS and SES to automate notifications for escalations, missed follow-ups, and appointment reminders.
Engineered an admin analytics dashboard using React + Zustand for tracking user activity, case completion rates, and compliance metrics.
Designed and implemented AI-driven features for task prioritization and patient risk classification using external API integrations.
Established a robust CI/CD pipeline using GitHub Actions and Docker, achieving automated testing, linting, and environment-based deployments.
Followed Agile ceremonies (daily standups, sprint planning, retros) while collaborating with QA, BAs, and PMs to deliver high-velocity features.
Led data protection efforts ensuring full GDPR compliance, including encrypted storage, session control, and user-consent management.
Delivered a fully responsive UI using DaisyUI-style components for mobile and tablet-first designs, achieving high Lighthouse scores.
Reduced support tickets by 40% by implementing detailed audit logging and a self-service helpdesk system in the admin interface.

Apr 2022 - Feb 2024

1 year 11 months

Austria

Full Stack Engineer

Porsche Informatik GmbH

Designed and deployed a mobile-first React Native app for AI-powered interactive storytelling, integrated with a backend using NestJS and AWS Lambda.
Created scalable, event-driven backend workflows using AWS Step Functions, managing asynchronous media generation tasks.
Built and secured REST APIs and WebSockets in NestJS, including validation (Zod-style), pagination, and rate limiting for safe consumption.
Designed and implemented relational models in PostgreSQL, optimized for large-scale content personalization and multilingual storage.
Leveraged Cognito for user authentication and role control, with custom user pools, triggers, and token lifecycle configuration.
Integrated AWS S3 for secure storage of images, audio, and user uploads; implemented lifecycle rules for cleanup and cost control.
Connected SES/SNS for user email verification, usage alerts, and marketing triggers.
Set up robust CI/CD automation with GitHub Actions, Docker, and Azure DevOps, supporting multiple testing stages and release channels.
Built AI prompt pipelines with GPT-4 for generating safe, age-appropriate content, and fallback handling for failures.
Created admin and parental dashboards using React and Zustand, supporting content approvals, session logs, and preference settings.
Reduced crash rates by 25% by instrumenting Sentry, AWS CloudWatch, and Firebase Performance Monitoring across the stack.
Delivered offline-first architecture, using caching and sync logic for low-connectivity scenarios.
Mentored 3 junior developers and introduced cross-squad documentation to scale velocity.
Maintained high test coverage with Jest, MSW, and React Testing Library, ensuring regression-free deployments.

Feb 2020 - Dec 2022

2 years 11 months

Austria

Senior Full Stack Developer

Toptal

Migrated a legacy monolith into modular NestJS microservices supporting inventory, order, and logistics domains.
Created highly available REST and Socket.IO-based APIs with auto-scaling support using Docker and Kubernetes.
Developed a PostgreSQL-backed event pipeline for warehouse operations, stock audits, and fulfillment tracking.
Built a web-based inventory control dashboard in React + Zustand, supporting role-based access and real-time data.
Engineered task scheduling tools with granular filters (SKU, supplier, urgency), similar to healthcare dispatch systems.
Integrated AWS SNS/SQS for decoupled service communication and order lifecycle automation.
Designed barcode and RFID scanning features in a React Native app, used in-store and in fulfillment centers.
Maintained user authentication with Cognito and OAuth2, using refresh tokens and RBAC enforcement.
Enabled offline-first stock reconciliation with delta sync and caching for mobile field devices.
Built audit trails and access logs for compliance and reporting needs.
Led sprint planning, backlog refinement, and code reviews for a 10-person full-stack team.
Reduced query latency by optimizing PostgreSQL indexes, materialized views, and cache layers (Redis).
Set up and maintained CI/CD with Azure DevOps, enabling automatic build, test, and blue/green deployments.
Aligned architecture with operational KPIs from cross-functional logistics and ops teams.

Jul 2019 - Feb 2020

8 months

Austria

Full Stack Engineer

Redox Interactive

Created a custom high-performance shopping platform with a mobile-first React.js/Next.js UI, leveraging Server-Side Rendering (SSR) to enhance SEO and cut page load times by 30%.
Engineered real-time inventory and checkout workflows using Node.js, Express.js, and TypeScript, integrated with AWS Lambda, DynamoDB, and PostgreSQL for accurate stock visibility, safe concurrency handling, and high-traffic resilience.
Deployed a robust payment and invoicing system supporting card payments, refunds, and tax-inclusive invoicing, incorporating Stripe APIs, secure payment flows, and email-based invoice delivery.
Architected a modular order management engine with support for cart persistence, discount logic, purchase history, and guest checkout — all exposed through RESTful APIs.
Implemented analytics and behavior tracking using Google Analytics, Mixpanel, and custom event pipelines, enabling actionable insights across user journeys, product performance, and conversion rates.
Optimized frontend performance with lazy loading, dynamic imports, and asset tuning via Next.js, React Query, and Tailwind CSS, ensuring seamless experiences across mobile and desktop.
Transitioned complex global state management from Redux to React Query and Zustand, improving maintainability, bundle size, and developer velocity.
Delivered secure authentication and session workflows with JWT, OAuth2, and MFA, ensuring privacy, account safety, and compliance with e-commerce security standards.
Expanded test coverage across the stack using Jest, React Testing Library, MSW, and Postman, reducing regression issues by 40% and improving deployment confidence.
Facilitated Agile ceremonies, led code reviews, and partnered with design and backend squads, shipping features through CI/CD pipelines in Azure DevOps.

May 2017 - Jan 2019

1 year 9 months

Hong Kong

Junior Full Stack Developer

SO technology

Supported internal tooling and mobile dashboards for SO technology, enabling scaled operations across logistics, product, and finance teams.
Developed and maintained high-visibility internal SPAs and dashboards using React.js, Vanilla JS, and jQuery, providing interactive data visualizations, real-time search filters, and drag-and-drop reporting features.
Built RESTful APIs and data models using Laravel (PHP 7, Symfony components) with PostgreSQL, enabling seamless integration between frontend dashboards and backend services.
Designed and deployed mobile-first dashboards with React Native (Expo), giving warehouse managers and field agents real-time access to logistics tools.
Integrated device capabilities such as barcode scanning, push notifications, and geolocation using Expo SDK modules to streamline delivery and tracking workflows.

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Transportation, Information Technology, Retail, Automotive, Healthcare, and Professional Services.

Transportation

Information Technology

Retail

Automotive

Healthcare

Professional Services

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, Project Management, Supply Chain Management, Logistics, and Operations.

Information Technology

Product Development

Project Management

Supply Chain Management

Logistics

Operations

Summary

Seasoned Senior Full Stack Engineer with 10+ years of experience building scalable web and mobile applications across real estate, fintech, gaming, and data-driven industries. Expert in JavaScript and TypeScript, with a strong focus on React, Next.js, Tailwind CSS, Node.js, Golang, .NET, and microservices. Proficient in developing SPAs, SSR apps, and microfrontends, and integrating RESTful APIs, GraphQL, event-driven systems, and cloud-native solutions using AWS, Docker, and CI/CD. Known for writing clean, performant code, leading Agile teams, mentoring engineers, and driving architecture that enhances scalability and delivery speed.

Skills

Frontend

Javascript
Typescript
React
React Native
React Hooks
Redux
Bootstrap
Jquery
Angular
Vue.js
Next.js
Tailwind Css
Mui
Flutter
Svelte.js
Nuxt.js
Vuex
Shadcn Ui
Responsive Design
Zustand
Pinia
Css3
Ngrx
Rx.js
Html5

Backend

Node.js
Typescript
Express
Nest.js
Rest
Graphql
Jwt
Oauth2
Rabbitmq
Kafka
Redis
Docker
Aws Lambda
Azure Devops
Postgresql
Mongodb
Mysql
Kubernetes
Grpc
Entity Framework Core
Prisma
C#
Asp.net Core
Github Actions
Terraform
Sentry

Others

Git
Github
Scrum
Agile
Google Analytics
Agile Methodologies
Problem-solving Abilities
Code Reviews
Database Management
Mentoring Junior Developers

Languages

Chinese

Native

English

Advanced

German

Intermediate

Education

Oct 2018 - Jun 2022

Graz University of Technology

Bachelor’s Degree in Computer Science · Computer Science · Graz, Austria · 3.9

Statistics

Experience

Total positions 5

Experience in Transportation 4.5 y

Avg length 1 y 8 m

Longest experience 2 y 10 m

Global Experience

Countries worked in 3 (Austria, Greece, Hong Kong)

Primary country Austria

Expertise

Recent roles Senior Full Stack Engineer, Full Stack Engineer, Senior Full Stack Developer

Main industries Transportation, Information Technology, Retail

Main business areas Information Technology, Product Development, Project Management

Qualifications

Highest degree Bachelor

Profile

Created

October 2025

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is David based?

David is based in Hallein, Austria.

What languages does David speak?

David speaks the following languages: Chinese (Native), English (Advanced), German (Intermediate).

How many years of experience does David have?

David has at least 8 years of experience. During this time, David has worked in at least 4 different roles and for 5 different companies. The average length of individual experience is 2 years and 6 months. Note that David may not have shared all experience and actually has more experience.

What roles would David be best suited for?

Based on recent experience, David would be well-suited for roles such as: Senior Full Stack Engineer, Full Stack Engineer, Senior Full Stack Developer.

What is David's latest experience?

David's most recent position is Senior Full Stack Engineer at Fractual.

What companies has David worked for in recent years?

In recent years, David has worked for Fractual, Porsche Informatik GmbH, and Toptal.

Which industries is David most experienced in?

David is most experienced in industries like Transportation, Information Technology, and Retail. David also has some experience in Automotive, Healthcare, and Professional Services.

Which business areas is David most experienced in?

David is most experienced in business areas like Information Technology, Product Development, and Project Management. David also has some experience in Supply Chain Management, Logistics, and Operations.

Which industries has David worked in recently?

David has recently worked in industries like Transportation, Retail, and Automotive.

Which business areas has David worked in recently?

David has recently worked in business areas like Information Technology, Product Development, and Project Management.

What is David's education?

David holds a Bachelor in Computer Science from Graz University of Technology.

What is the availability of David?

David is immediately available full-time for suitable projects.

What is the rate of David?

David's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.