Stefan Tudor Dediu, Developer in Bucharest, Romania
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Stefan Tudor Dediu

Bio

Stefan has more than 15 years of experience in software development, working in various environments ranging from tech startups to enterprise companies. With expert skills in multiple technologies such as PHP, JavaScript, and Swift, which are his particular strengths, he has focused on building innovative and interesting projects as a freelancer.

Portfolio

Asociatia Pentru Dezvoltare Urbana
JavaScript, Node.js, Angular, Swift, Artificial Intelligence (AI)...
Tei Software Studios
JavaScript, Angular, PHP, Node.js, Swift, Android, Java, .NET, TensorFlow...
MediCircle
Node.js, React, Amazon Web Services (AWS), FedEx API, Cypress, API Integration...

Experience

  • PHP - 15 years
  • Java - 12 years
  • Swift - 7 years
  • Objective-C - 6 years
  • Android - 5 years
  • Angular - 4 years
  • Node.js - 4 years
  • React - 3 years

Preferred Environment

MacOS, PhpStorm, Xcode, Visual Studio Code (VS Code)

The most amazing...

...thing I've accomplished is building TactileImages, a software solution designed to help blind or visually impaired people using AI and machine learning.

Work Experience

Lead Software Developer

2019 - PRESENT
Asociatia Pentru Dezvoltare Urbana
  • Selected the core technologies, languages, and frameworks fit for all the aspects of the project, responsible for designing the application architecture.
  • Managed all aspects of the software development process and coordinated the rest of the team.
  • Involved directly in writing the code for several software components of the solution, specifically the mobile, web, and AI.
  • Deployed and launched the web and mobile apps on Microsoft Azure and AppStore.
Technologies: JavaScript, Node.js, Angular, Swift, Artificial Intelligence (AI), Machine Learning, MySQL, Azure, Express.js, TypeScript, API Architecture, REST, Application Architecture, API Integration, Technical Leadership, Cloud Architecture, Back-end, REST APIs, Full-stack Development, Full-stack, Startups, Front-end, Third-party APIs, APIs, Software Architecture, Microsoft Azure, Next.js, Authentication, Deployment, OpenAI API, FastAPI, Python, Scalable Architecture, Agile Software Development, Back-end Architecture, Back-end Development, Cloud Infrastructure, Figma, AI Design, Responsive Web Design (RWD), Web Development, UI Design, GitHub, JSON, SQL, CTO, AI-generated Code, Claude Code, Google Cloud Platform (GCP), AI Tools, HTML, Workflow, Workflow Automation & System Integration, REST API Architecture, Redis, Anthropic, OpenAI, App Store, Push Notifications, Mobile, Minimum Viable Product (MVP)

Senior Full-stack Developer, Software Architect

2014 - PRESENT
Tei Software Studios
  • Developed multiple projects at my consultancy and software development company. I managed a team of 7-10 people, including software developers, graphic designers, and testers.
  • Built an online video training platform that enrolled more than a thousand subscriptions and six-digit sales the first week after the launch. It was seamlessly integrated with the existing company's other products.
  • Managed the development of the mobile and web applications for a modular, scalable, and integrated IoT platform. The platform was awarded the 2019 Honorable Mention at Microsoft HQ Romania.
Technologies: JavaScript, Angular, PHP, Node.js, Swift, Android, Java, .NET, TensorFlow, Azure, Amazon Web Services (AWS), Objective-C, Vue, Laravel, React, TypeScript, Express.js, SlimPHP, CakePHP, API Architecture, Application Architecture, Web Application Architecture, Architecture, API Integration, Technical Leadership, Cloud Architecture, Back-end, REST APIs, Full-stack Development, Full-stack, Startups, Mobile Development, Mobile Apps, Video Streaming, Front-end, Third-party APIs, APIs, Cross-platform App Development, PostgreSQL, Mobile App Development, Software Architecture, Amazon S3 (AWS S3), iOS, Medical Software, Google Calendar API, OpenAI GPT-4 API, Email, Next.js, Authentication, Deployment, OpenAI API, Supabase, Real-time Systems, FastAPI, Python, Scalable Architecture, Agile Software Development, Back-end Architecture, Back-end Development, Cloud Infrastructure, Figma, Django, AI Design, Payment APIs, Responsive Web Design (RWD), Claude Code, Web Development, UI Design, Healthcare, GitHub, JSON, XML, Data Processing Automation, Document Parsing, MongoDB, SQL, AWS Cloud Architecture, AI-generated Code, Cursor AI, Google Cloud Platform (GCP), AI Tools, HTML, Workflow, Workflow Automation & System Integration, REST API Architecture, Agentic AI, Redis, Anthropic, OpenAI, Redux, HIPAA, Healthcare & Insurance, App Store, Push Notifications, Mobile, Messaging, Video Processing, Minimum Viable Product (MVP), AI Pipeline

Senior Full-stack Developer

2022 - 2022
MediCircle
  • Developed the front end and back end for the MediCircle platform, a platform that facilitates access to cancer treatment and medication.
  • Took responsibility for third-party and API integrations: FedEx (address validation, shipping labels generation), Pioneer, Lexicomp, Cypress.
  • Implemented the deployment environment and pipelines using AWS services and GitLab CI/CD. The required pipeline passes included Prettier, Lint, and Cypress tests.
Technologies: Node.js, React, Amazon Web Services (AWS), FedEx API, Cypress, API Integration, Back-end, REST APIs, Full-stack Development, Full-stack, Startups, Front-end, Third-party APIs, APIs, PostgreSQL, Medical Software, Authentication, Deployment, Agile Software Development, Back-end Development, UI Design, Healthcare, GitHub, JSON, SQL, AWS Cloud Architecture, HTML, Workflow, REST API Architecture, Healthcare & Insurance, Minimum Viable Product (MVP)

Full-stack Developer

2011 - 2015
Freelance Work
  • Created more than six eCommerce stores, helping offline shops expand their businesses online.
  • Automated and optimized the back end for an online educational platform for kids improving content management and deployment by over 20%.
  • Developed an ERP for a telecommunications company helping them manage their clients, employees, staff, projects, invoices, and reports.
Technologies: PHP, JavaScript, Laravel, CakePHP, SlimPHP, Java, .NET, HTML, CSS, jQuery, MySQL, Yii, Back-end, REST APIs, Full-stack Development, Full-stack, Startups, Front-end, APIs, Authentication, Deployment, Agile Software Development, Back-end Development, GitHub, JSON, XML, Document Parsing, SQL, Workflow, Workflow Automation & System Integration, REST API Architecture, App Store, Push Notifications

Lead Software Developer

2005 - 2011
Ipsos Interactive Services SRL
  • Managed a team of software developers to create web projects according to custom client specifications.
  • Created internal apps and tools, reducing the development time for certain products by more than 30%.
  • Contributed to the creation and validation of workflows, procedures, and best practices.
  • Developed and successfully launched more than 100 individual projects of different sizes and complexity along with my team.
Technologies: PHP, JavaScript, HTML, CSS2, SPSS, IBM SPSS, jQuery, .NET, Technical Leadership, Authentication, Back-end Development, GitHub, JSON, XML, Document Parsing, SQL, Workflow Automation & System Integration

Experience

TactileImages

https://tactileimages.org
In charge of management and full-stack development for TactileImages, a software solution designed to help blind or visually impaired people. The AI and machine learning solution uses the mobile device's camera to track the position of the user's hand and fingers and provide audio descriptions while exploring images. The software solution offers a web platform for teachers and contributors to create and manage the content.

The platform has a social component — used in schools, it offers visually impaired children the opportunity to study independently. With a mobile app that describes interactive drawings with raised surfaces just like a specialist, they can discover all the things they cannot touch and the world by themselves.

Communications iOS App - VoIP Calls, Messages, and Chat

A Swift-based calling solution on iOS for sales teams. The mobile app enables sales teams to use different phone numbers, make audio calls, and message potential leads. I managed the iOS mobile development as a senior iOS developer and led a small mobile team of three developers.

In addition to development, I designed the mobile app's architecture and acted as product owner for the mobile apps.

Social App for Mentoring Platform

A Swift-based iOS mobile app used for a mentoring platform. It allowed members to post on their feeds, achieve specific goals, and communicate with each other

I was the senior iOS developer in charge of the mobile app architecture and development. I used WebRTC to enable audio and video calls and Socket.IO to enable real-time chat conversations between app users.

Social App for Streaming and Video Engagement

A Swift-based app for communities that want to share their experiences.

The app allowed users to do online viewing sessions on shared content. The sessions could be on the fly or scheduled for later dates and were available to groups of up to eight users.

I oversaw iOS development, implementing new features, maintaining and refactoring code, optimizing app performance, and working with the AWS Chime team.

AI App That Creates Custom Stories for Kids

I worked on an innovative app that utilized the ChatGPT API to create custom stories for kids. This application allowed parents to customize stories based on multiple inputs, such as their child's age, interests, desired teachings, and preferred characters. My primary responsibility was managing the back-end development and integrating ChatGPT seamlessly into the application.

I designed and implemented the back-end architecture, ensuring efficient communication between the app and the ChatGPT API. This involved creating endpoints to handle user inputs, processing these inputs to generate appropriate prompts for the API, and managing the responses to deliver engaging and coherent stories. Throughout the project, I focused on ensuring the system was scalable, secure, and responsive.

By effectively integrating ChatGPT, we were able to offer a unique and interactive storytelling experience, making the app a valuable tool for parents and an engaging platform for children. This project highlighted my ability to leverage advanced AI technologies to develop practical, user-friendly applications.

Assistant GTP Chat iOS App

I worked on an AI-powered productivity app that combines a GPT-driven chat assistant with smart integrations, including Gmail, Google Calendar, Apple In-App Purchases, and WhatsApp, to help professionals manage their day more effectively.

My responsibilities spanned both back-end development and the iOS application. On the back-end, I designed and implemented the full Cognito architecture using Node.js and PostgreSQL, including RESTful API endpoints, real-time communication via WebSockets for live conversation presence and messaging, and background job processing for async AI tasks such as email draft generation. I handled user authentication using JWT and Amazon Cognito, and managed deployment and infrastructure on AWS.

A core part of the project was the AI integration: I engineered the system that constructs context-aware prompts enriched with the user's profile, and calls the OpenAI API to generate relevant, actionable insights. The assistant is backed by the OpenAI Assistants API, enabling persistent, context-aware conversations.

Quit Drinking iOS App

I worked on an innovative iOS app for alcohol reduction and a mindfulness tool. The application helps users track sobriety, manage cravings, and build healthier habits through a combination of behavioral science techniques and AI-powered insights.

My primary responsibility was developing the iOS application and back end using SwiftUI and Node.js, architecting the core features from the ground up — including a 30-day CBT-based challenge system, a daily clarity check-in system, an SOS crisis support modal with guided exercises, and an AI-assisted journaling feature powered by the OpenAI API.

I designed and implemented the journaling feature end-to-end, integrating a large language model (LLM) via the OpenAI API to provide users with personalized, context-aware reflections based on their journal entries, sobriety progress, and emotional check-in data. This involved crafting dynamic prompts that combined user-specific context, such as days sober, recent clarity ratings, and drinking patterns, to generate meaningful, supportive insights rather than generic responses.

Healthcare Logistics Platform

A healthcare logistics platform that connected patients with donors. I architected and implemented the flows and automations for a medical distribution network's logistics. The system handled the full process end-to-end: generating internal orders based on stock levels and availability pulled from multiple internal systems, matching those orders with patient requirements, integrating with Stripe for payments and FedEx for shipping, and tracking every step through to final delivery.

Event Analytics Dashboard

I worked on a comprehensive analytics and event tracking platform designed to give mobile app teams full visibility into user behavior across their iOS applications. The platform enables tracking of onboarding funnels, paywall performance, app sessions, feature usage, and app rating requests.

My primary responsibility was designing and building the entire stack, from the back-end infrastructure to the reporting portal. On the back end, I architected a RESTful API with secure authentication layers, JWT for dashboard users, and HMAC-signed requests for mobile clients, as well as a per-project API key system that allows iOS teams to integrate directly without going through the dashboard.

On the front end, I built the reporting portal in React: a full dashboard that presents all tracked data to users, including funnel visualizations, paywall analysis, session stats, and feature usage breakdowns. The portal consumes the API directly and is designed to give both technical and non-technical stakeholders a clear view of how their apps are performing.

Hospital Internal Communications Portal

A Communications Portal that connects doctors and patients through video stream and text. I was in charge of creating the architecture, implemented all backend services and WebRTC support for live streaming, integrated the system with other hospital systems and workflows.

eCommerce Platform for Personalized Digital Products

A custom eCommerce platform built to support a conversion-focused checkout experience for digital products. Users arrived through paid advertising campaigns, moved through a guided funnel, customized their product, completed payment, and had their orders processed and shipped.

I implemented both the front-end (React) and back-end (Node.js) components of the platform, including the checkout workflow and Stripe payment integrations using both redirect-based and embedded solutions. As part of the funnel optimization team, I was actively involved in monitoring and analyzing user behavior across the onboarding and checkout funnels, tracking key metrics such as Conversion Rate and identifying drop-off points. I contributed to conversion rate optimization (CRO) efforts by monitoring, analyzing, proposing, and implementing improvements to the onboarding steps, product customization flow, and checkout experience to increase overall conversions while maintaining a reliable and scalable payment process.

Server-side Rendering Platform for a Computer Games Company

A server-side rendering platform designed to generate SEO-optimized static websites from a large database of browser-based video games. The system transformed structured game data into fully rendered static pages, allowing the client to publish and maintain a large network of high-performance content sites.

I was part of the team responsible for implementing and automating the full generation pipeline, from back-end content processing to static site creation and deployment. I worked primarily on the back end using Laravel, building the systems that generated the static content and orchestrated the rendering workflow. On the front-end side, I implemented the generated pages using HTML, CSS, and JavaScript to ensure fast load times and search-engine-friendly output. The project focused heavily on server-side rendering, static site generation, and performance optimization to maximize SEO visibility and efficient content delivery.

High-scale Advertising Platform Optimization & Sharding

I worked on a high-traffic advertising network (millions of monthly users) that faced scalability issues in its PHP-based ad-serving infrastructure. Using New Relic, I identified performance bottlenecks across the application and database layers, focusing on slow queries, inefficient indexing, and high-load endpoints. Implemented query optimizations, indexing strategies, and improved data access patterns, resulting in a 10× improvement in database performance. Additionally, I designed and implemented a database sharding strategy to distribute traffic across multiple MySQL instances, significantly improving scalability, fault tolerance, and system stability under heavy load.

SSR Learning Platform with Redis Caching (Vue and Laravel)

Developed a video-based learning platform focused on mentoring and specialization. The architecture consisted of a Vue front end and a Laravel back end, with Sanctum authentication. Implemented server-side rendering (SSR) to improve SEO and reduce time-to-content for content-heavy pages. Introduced Redis caching for frequently accessed data and user-related actions, significantly reducing database load and improving response times. Worked on optimizing API interactions and ensuring smooth integration between frontend and back end while maintaining performance under growing traffic.

High-traffic Game Portal Network with Static Generation & Caching

Built and maintained a network of browser-based gaming websites serving over 10,000 daily users. Developed a Laravel-based system that dynamically generated multiple static game portals from a centralized database, each with its own templates, rules, and configurations. Designed and implemented custom Nginx configurations for each site to optimize caching strategies, static content delivery, and request handling. This architecture enabled efficient scaling, reduced back-end load, and ensured fast page delivery across all portals.

AI-powered Environmental Intelligence Platform

I built an AI-powered environmental intelligence platform that provides early warning of drought and wildfire risk using satellite remote sensing and ground weather station data. I designed and implemented the full system architecture: satellite data ingestion (Copernicus Sentinel-2 NDVI), weather station integration (AEMET OpenData API with 21 stations), z-score anomaly detection engine, composite risk scoring for both drought and fire, multi-tier alert system, REST API (FastAPI), and interactive map visualizations (Folium). I also implemented sub-localization with 25 monitoring zones and validated against 6 known historical events — 100% detection rate: drought detection averaged 149+ days before official declarations, wildfire risk flagged 35+ days before ignition.

Legal Compliance & Litigation Management Platform for Public Institutions

I worked on a compliance and litigation management platform designed for public institutions, helping them track court cases, audit findings, and regulatory deadlines in one centralized system.

My responsibilities spanned back-end development and the React front end. On the back end, I designed and implemented the full architecture using Node.js (Express) and PostgreSQL with Sequelize ORM, including RESTful API endpoints, session-based authentication with JWT support, and background job processing powered by BullMQ and Redis for asynchronous tasks such as email notifications and scheduled litigation updates. I managed deployment and infrastructure on AWS, using CloudFormation (SAM) templates to provision VPCs, RDS instances, and S3 buckets, along with AWS SES for transactional email delivery.

A core part of the project was the integration with the Romanian court system (JUST portal), where I engineered SOAP-based XML queries to automatically import and sync litigation case data (including court details, parties, hearing stages, and solutions) on a recurring schedule. The platform also features a robust notification system with MJML email templates, a multi-role access model (Admin, Principal, Secondary users), among others.

Education

2009 - 2011

Master's Degree in Project Management

University of Economic Sciences Of Bucharest, Faculty of Cybernetics, Statistics and Informatics - Bucharest, Romania

2001 - 2006

Bachelor's Degree in Computer Science

University Politehnica Of Bucharest - Faculty of Automatic Control and Computer Sciences - Bucharest, Romania

Certifications

JANUARY 2016 - PRESENT

Responsive Website Development and Design

University of London | via Coursera

DECEMBER 2015 - PRESENT

Introduction to Meteor.js Development

University of London | via Coursera

MARCH 2014 - PRESENT

Programming Mobile Applications for Android Handheld Systems

University of Cambridge | via Coursera

DECEMBER 2012 - PRESENT

Object Oriented Programming in Java

University of London | via Coursera

JUNE 2000 - PRESENT

Certificate in Advanced English

University of Cambridge

Skills

Libraries/APIs

Node.js, React, REST APIs, OpenAI API, Vue, Google Calendar API, Claude API, Stripe, TensorFlow, jQuery, FedEx API, Twilio API, Socket.IO, WebRTC, WhatsApp API, Pandas, NumPy

Tools

Claude, Claude Code, GitHub, PhpStorm, Xcode, SPSS, IBM SPSS, CallKit, Amazon Cognito, ChatGPT, Figma, Amazon Simple Email Service (SES), AWS CloudFormation, Sequelize

Languages

Swift, PHP, HTML, TypeScript, XML, Java, C++, JavaScript, Objective-C, CSS, Python, SQL, CSS2

Frameworks

Laravel, Express.js, Next.js, Angular, CakePHP, Yii, Django, Redux, .NET, Cypress, Core Data, EventKit, JSON Web Tokens (JWT)

Paradigms

API Architecture, Web Application Architecture, Mobile Development, Agile Software Development, Back-end Architecture, Responsive Web Design (RWD), UI Design, REST API Architecture, REST, Application Architecture, Real-time Systems, HIPAA Compliance, Conversion Rate Optimization (CRO), Search Engine Optimization (SEO), Model View ViewModel (MVVM)

Platforms

iOS, MacOS, Visual Studio Code (VS Code), Android, Amazon Web Services (AWS), Google Cloud Platform (GCP), Mobile, Azure

Storage

SlimPHP, PostgreSQL, JSON, Databases, MySQL, Amazon S3 (AWS S3), MongoDB, Redis, Cache, SQLite

Industry Expertise

Healthcare

Other

Artificial Intelligence (AI), English, APIs, Architecture, API Integration, Back-end, Full-stack Development, Technical Leadership, Full-stack, Software Architecture, Startups, Mobile App Development, Mobile Apps, Video Streaming, Third-party APIs, Front-end, Medical Software, WebSockets, AI Integration, Large Language Models (LLMs), Authentication, FastAPI, Back-end Development, AI Design, Web Development, Document Parsing, AI-generated Code, AI Tools, Prompt Engineering, Anthropic, OpenAI, App Store, Push Notifications, Messaging, Minimum Viable Product (MVP), AI Pipeline, Algorithms, Operating Systems, IT Project Management, Web Project Management, Machine Learning, Cloud Architecture, Cross-platform App Development, Microsoft Azure, OpenAI GPT-4 API, Email, Deployment, Supabase, Scalable Architecture, Cloud Infrastructure, Payment APIs, Data Processing Automation, AWS Cloud Architecture, Cursor AI, Conversion Rate, Security, eCommerce, Workflow, Workflow Automation & System Integration, Server-side Rendering (SSR), Static Site Generators, Agentic AI, HIPAA, Healthcare & Insurance, Location Services, Maps, Networks, Calendars, Amazon Chime, Amazon Chime SDK, Portals, Platforms, Healthcare IT, CTO, HeyGen, Database Optimization, Database Table Optimization, Sharding, Performance, Caching, Business Services, Laravel Sanctum, Static Site Development, Infrastructure, Satellite Images, Sentinel 2, Geospatial Data, Geospatial Analytics, Video Processing

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