Steven Don
Verified Expert in Engineering
Software Developer
Etten-Leur, Netherlands
Toptal member since September 25, 2026
Steven is a full-stack engineer with 25 years of experience building and scaling web platforms that power multi-million-euro businesses. Specializing in PHP, WordPress, Laravel, Node.js, Python, and modern JavaScript/TS frameworks (React, Next.js, Vue, Angular), he delivers robust systems integrated with Salesforce, Stripe, Exact Online, and AI tools (ChatGPT, Claude). Clients value his ability to look beyond technical requirements and solve business challenges with reliable, scalable solutions.
Portfolio
Experience
- PHP - 20 years
- React - 12 years
- Python - 12 years
- Node.js - 12 years
- TypeScript - 10 years
- Django - 9 years
- Laravel - 8 years
- Next.js - 8 years
Preferred Environment
Full-stack Development, Front-end Development, Back-end Architecture, API Integration, Node.js, Python, PHP, JavaScript, TypeScript, AI Integration
The most amazing...
...system I've built is a web infrastructure powering dozens of trade publications and industry events for a leading B2B media company.
Work Experience
Stuff Full-stack Engineer
ProMedia Group
- Designed and delivered end-to-end platforms spanning B2B media, events, trade publications, conferences, healthcare, insurance, and AI-driven products, covering content management, registrations, access control, ML inference, and business workflows.
- Led end-to-end development of serverless full-stack systems using Node.js, Django, React 18, Angular, and AWS ECS for high-traffic fintech, education, media properties, and eCommerce platforms, implementing gRPC microservices and Kafka event streams.
- Designed/deployed FastAPI-based ML inference APIs for NLP-driven legal and healthcare document classification, delivering real-time predictions with 99.9% uptime and low-latency streaming, integrating with Salesforce, Exact Online, n8n, and Pardot.
- Built full-stack AI platforms combining React/Next.js with Python/Django microservices, with interactive model feedback, retraining workflows & production-grade intelligent UX for access control & automation of CRM, marketing, & financial processes.
- Architected cloud-native infrastructure on AWS ECS/Fargate, Azure, Digital Ocean, Tencent Cloud with Docker, Kubernetes & CI/CD automation for Github/Gitlab, supporting multi-environment rollouts, container orchestration, & zero-downtime deployments.
- Modernized legacy applications and development workflows by introducing cleaner architecture, automated testing, reusable components, and modern Laravel and JavaScript practices while maintaining continuity for established products.
- Rebuilt the development workflow around AI-first engineering using Cursor, Claude Code, Codex, and LLM APIs, applying AI throughout architecture, implementation, debugging, testing, refactoring, and code review.
- Designed cloud-native solutions using AWS, Docker, Kubernetes, event-driven services, GraphQL, RabbitMQ, and Kafka, applying scalable architecture patterns across distributed production systems.
- Built reusable UI libraries and design systems with Tailwind, Storybook, and TypeScript, while optimizing Next.js applications with SSR/ISR/SSG and Vite/Webpack for superior Core Web Vitals.
- Established production observability with Prometheus, Grafana, and CloudWatch, mentored engineers on MLOps and scalable architecture, and reduced deployment friction by 40% through robust CI/CD pipelines.
Co-founder
NN Software
- Founded and developed commercial software products across desktop, mobile, and systems programming environments, taking products from initial concept through implementation and deployment.
- Designed and developed Windows applications using C++, DirectX, and low-level programming techniques for interactive and performance-sensitive software.
- Built mobile games and applications for Nokia devices using Java, adapting software architecture and user experiences to constrained mobile hardware and platforms.
- Developed reusable software components and tools that accelerated implementation across multiple projects and reduced duplicated development effort.
- Designed application architectures, implemented core functionality, and managed technical decisions across the complete software development lifecycle.
- Delivered customer-focused software by translating business requirements into practical technical solutions while working directly with users and stakeholders.
- Maintained and extended production software over time, diagnosing complex technical issues and implementing improvements without disrupting existing functionality.
- Conducted technical workshops and programming sessions, sharing practical software development knowledge and helping developers build stronger programming fundamentals.
Web Developer
Netvlies Internetdiensten
- Owned technical design and implementation for client websites, including Playboy Netherlands, the Playboy Cyberclub, and Nieuwe Revu.
- Delivered websites for public library organizations, including Bibliotheek Arnhem, Bibliotheek Lek & IJssel, and Bibliotheek De Kempen.
- Developed dynamic websites and web applications using PHP, JavaScript, HTML, CSS, and relational databases for commercial clients.
- Built database-driven web solutions that combined server-side business logic with interactive browser-based interfaces and content management functionality.
- Translated client requirements into practical web applications, working across analysis, architecture, development, testing, deployment, and ongoing maintenance.
- Implemented reusable PHP components and JavaScript functionality to streamline development and provide consistent behavior across multiple client projects.
- Integrated external services and data sources into web applications, connecting business processes with custom online platforms and databases.
- Diagnosed and resolved production issues across application code, databases, hosting environments, and integrations to maintain reliable client websites.
- Collaborated directly with clients and project stakeholders to refine requirements, explain technical options, and deliver solutions aligned with business needs.
Network Administrator
Amlin Holding BV
- Managed network administration for the organization.
- Maintained the company's Advanced Planning System, built on FileMaker Pro.
- Provided hands-on technical support and troubleshooting for network infrastructure and business systems, addressing operational issues and maintaining system availability.
Co-founder
ZZICT
- Co-founded the IT company, responsible for network administration and Windows software development.
- Developed PC games for DirectX/Windows and mobile games in Java for Nokia Series 60 devices.
- Continued freelance collaboration with the company after stepping back from full-time employment in 2003.
Lead Game Programmer
Crytek Studios
- Led programming on the "Silent Space" project. The title was not completed for business and legal reasons unrelated to the engineering work.
- Worked on game systems and programming within a professional game development environment at Crytek Studios in Coburg, Germany.
- Contributed to the development of Silent Space, applying C/C++ programming and game development experience to a commercial PC game project.
Student Assistant
Tilburg University (Katholieke Universiteit Brabant)
- Delivered practical workshops for the Computer Infrastructure course, helping students understand computer systems, networking, and infrastructure concepts.
- Tutored students in Turbo Pascal alongside the university's Programming course.
- Supported university teaching activities as a student assistant while completing studies in Business Information Technology.
Systems Developer
Streekomroep Weert
- Designed and built the automated overnight broadcast system for local radio station Streekomroep Weert.
- Ensured that the system interfaced directly with the broadcast signal and could record and schedule programs for playback, including automatic shortening or lengthening of segments.
- Implemented automatic audio duration adjustment, enabling recorded programs to be shortened or extended to fit scheduled broadcast time slots.
Experience
Virtu-Sign — Digital Signature & Document Platform
https://virtu-sign.comI was responsible for implementing core workflows, integrating application services, handling data and security requirements, and building reliable user-facing functionality. I also handled debugging, testing, performance improvements, and integrating the different components into a cohesive production platform.
3D Bomber
https://www.shdon.com/software/games/3dbomberYou can either play this game against the PC or against a fellow human player over a modem or a serial cable. I would seriously recommend playing against a friend, as the PC player is rubbish and offers little competition.
The Misadventures of Jeffrey Jetsam
https://www.shdon.com/software/games/jeffrey-jetsamCustom Web Applications
MerlinFit — Fitness & Wellness Platform
https://merlinfit.com/I was involved in translating product requirements into production-ready features, implementing business logic and data workflows, integrating APIs, and improving the platform's overall reliability and usability. I also handled debugging, performance improvements, and ongoing development across the application.
Knowlee AI
https://knowlee.aiThe work required adapting quickly to different technology stacks and business requirements while maintaining reusable engineering practices across products. I worked directly with founders, product teams, and clients to turn ambiguous requirements into production-ready systems and continued supporting the products as they evolved.
I worked across the full stack, building back-end services, APIs, AI integrations, data workflows, and responsive front-end functionality. Technologies included Python, APIs, React/Next.js, databases, and modern AI tooling.
ProMedia Group — B2B Media & Event Platforms
https://promedia.nlI also developed integrations with Salesforce, Exact Online, and Pardot, connecting internal applications to CRM, marketing, and business management workflows. My responsibilities included architecture, implementation, debugging, performance optimization, deployment, and ongoing production support.
Financial Analytics & Business Origination Platform
A key component was a decision engine that combined application information with credit and pricing models to automate approval decisions. I worked with Ruby, Clojure, Angular, React, R, and Python, integrating analytical models into production workflows and improving the speed and consistency of application processing.
Education
Bachelor's Degree in Information Management
Tilburg University - Tilburg, Netherlands
Certifications
Claude Academy: AI Fluency for Builders
Anthropic
Claude Academy: AI Capabilities and Limitations
Anthropic
Claude Academy: Claude with Google Cloud's Vertex AI
Anthropic
Advanced Python with TDD, Clean Architecture
Codecademy
ReactJS, Hooks, Recoil, TDD, Clean Architecture and SOLID
Codecademy
Advanced Node.js with TDD, Clean Architecture and TypeScript
Codecademy
Skills
Libraries/APIs
DirectX, OpenGL, React, Node.js, Stripe, GraphQL API, REST APIs, Claude API, Playwright, FFmpeg, React Redux, React Router, Three.js, WebRTC, WebXR, Entity Framework, Puppeteer, API Development, SharePoint API, Context API, Mantine, Twilio API, Google Merchant Center API, Vue, Google Calendar API, Geofencing API, Web3.js, Graph API, Stripe API, OpenID, Vue 3, Pydantic, Google Sheets API, HLS.js, React Query, PostgREST, Google Play API, Tokio
Tools
Trello, GitHub, GitLab, Pardot, FileMaker Pro, Turbo Pascal, Visual Studio, Microsoft Access, Claude Code, Microsoft Power Apps, ChatGPT, Claude, Claude Agent SDK, Apache Maven, Auth0, Codex, ComfyUI, Jira, Slack, Amazon EKS, Grafana, AWS Step Functions, AWS Cloud Development Kit (CDK), Amazon Cognito, Git, RabbitMQ, Amazon Simple Queue Service (SQS), Prisma, Firebase Authentication, Celery, TestFlight, Drizzle ORM, Helm, NGINX, Google Workspace, Pytest, Terraform, Spreadsheets, Astro, Google Sheets, PlayReady, Salesforce DX, n8n, Zapier, Sentry, Turbo, Expo, Amazon Simple Notification Service (SNS), Firebase Cloud Messaging (FCM), GIS, Dynamics 365 Business Central, SMART on FHIR, Amazon OpenSearch, Exact ERP
Languages
PHP, C++, JavaScript, HTML, SQL, TypeScript, CSS, Java, C, Pascal, Delphi, Visual Basic, Python, C#, GraphQL, Kotlin, HLSL, Rust, Google Apps Script, Groovy, XML, Python 3, Swift, ECMAScript (ES6), HTML5, CSS3, BrightScript, Go, Regex
Frameworks
Redux, Spring Boot, Laravel, Zope, Next.js, Django, Tailwind CSS, Electron, Agentic Frameworks, JSON Web Tokens (JWT), OAuth 2, React Native, Vanilla JS, Angular, Express.js, .NET, .NET Core, ASP.NET, Scrapy, Selenium, NestJS, CodeIgniter, ThinkPHP, Flask, Recoil, Fastify, Jest, Spring Microservice, LangGraph, Nuxt 3, Nuxt.js, LightningJS, Django REST Framework, Payload CMS, AdonisJS
Paradigms
Windows App Development, Desktop App Development, Clean Code, REST, Microservices, Object-oriented Design (OOD), Stress Testing, Asynchronous Programming, Back-end Architecture, Model Context Protocol (MCP), Role-based Access Control (RBAC), Test-driven Development (TDD), Event-driven Architecture, DevOps, Automated Testing, Search Engine Optimization (SEO), ACID, ETL, Automation, Continuous Delivery (CD), Continuous Integration (CI), Application Architecture, Testing, Test Automation, Fast Healthcare Interoperability Resources (FHIR)
Platforms
Windows, MacOS, Linux, Visual Studio Code (VS Code), WordPress, Salesforce, Google Cloud Platform (GCP), Azure, Azure Functions, Microsoft Power Automate, Microsoft Power Platform, Vercel, Twilio, Amazon Web Services (AWS), Desktop, Docker, Kubernetes, Android, Ubuntu, Grok, MetaTrader 4 (MT4), MetaTrader 5 (MT5), MetaTrader, MetaTrader 4, MetaTrader 5, SharePoint, Shopify, Vertex AI, DigitalOcean, WooCommerce, Apache Kafka, Oracle, Magento 2, Magento, Firebase, Google AppSheet, Cloud Run, tvOS, Harness, Oracle Cloud Infrastructure (OCI), Mobile, Replit, iOS, SharePoint 365, Blockchain, Microsoft Dynamics 365, Clerk, Telnyx
Storage
Databases, MySQLi, PostgreSQL, MySQL, Datadog, MongoDB, Elasticsearch, Microsoft Entra ID, JSON, Database Performance, Redis, Data Pipelines, Microsoft SQL Server, Relational Databases, Amazon DynamoDB, Google Cloud SQL, SQLite, Google Cloud, Cloud Firestore
Industry Expertise
Trading Systems, Project Management, Insurance
Other
Software Development, Information Systems, Management Information, Software Engineering, Full-stack, Web Development, Game Development, CMS, API Integration, Exact Online, Software, Network Administration, IT Infrastructure, Applications, Audio Processing, Open Broadcaster Software (OBS), Multimedia Processing, System Integration, Automated Data Flows, Artificial Intelligence (AI), Vite, Full-stack Development, Microsoft Dataverse, Data Engineering, AI Tools, AI-assisted Development, Supabase, SaaS, AI Agents, Microsoft Azure, Document Parsing, Web Applications, AI Automation, CSV, Data Processing, Workflow Automation, Architecture, Desktop App, FastAPI, Language Server Protocol (LSP), Project Consultancy, Front-end Development, Agentic AI, Dashboards, Data Visualization, LangChain, OAuth, OpenID Connect (OIDC), AI Development, Streaming, Videos, Cloud Storage, Transcoding, Healthcare Software, Technical Leadership, Delivery Management, CI/CD Pipelines, Front-end, Back-end, Cloud Platforms, Distributed Systems, SQL Server, AI Engineering, Agentic Coding, WebSockets, AI-generated Video, Cursor AI, Generative Artificial Intelligence (GenAI), Large Language Models (LLMs), OpenAI, OpenRouter, Payment Gateways, CAPTCHA, Facebook, Web Scraping, Proxies, APIs, Payments, Solution Architecture, Fintech, Financials, Vibe Coding, AI Compliance, Enterprise Systems, Third-party APIs, Third-party Integration, Authentication, Finance, Global Banking, Data Quality, Data Quality Governance, Data Quality Management, Data Lineage, Data Governance, Statistics, Optimization, LLM Integration, Software Architecture, Go-to-market (GTM) Strategy, Product Roadmaps, Early-stage Startups, Education Technology (Edtech), Leadership, Multi-tenant Architecture, Multi-tenant SaaS, Startups, Concurrency, Database Optimization, Scripting, Equity Trading, AI Agent Orchestration, Forex Trading, Options Trading, Shell Scripting, Stock Trading, Trading, Document Management, Microsoft 365, Office 365, Data Loss Prevention (DLP), Microsoft Purview, HTTP, OData, Collaboration, Challenge-based Learning, Communication, Agile Sprints, Code Auditing, Inventory Management, Lightspeed, eCommerce, Plugins, React Hooks, Web MVC, Event-driven Systems, Hospitality, OpenTelemetry, Cdata, Enterprise Performance Management (EPM), Multi-agent Systems, Authorization, Webhooks, Integrations, Booking Apps, Booking Systems, Customer Relationship Management (CRM), Azure Blob Storage, Core Web Vitals, Google Analytics 4 (GA4), Performance Optimization, WordPress Plugins, Yoast SEO, Data Modeling, Enterprise Architecture, Design Systems, User Experience (UX), User Interface (UI), Accessibility, Search Engines, WCAG 2, High Availability (HA), Reporting, Reports, State Machines, AI Integration, Application Security, Cloud Infrastructure, Code Review, Amazon RDS, Optical Character Recognition (OCR), Calendars, Firebase Cloud Functions, Push Notifications, RESTFul APIs, Email Authentication, User Authentication, Cloudflare, Financial Systems, Crypto, Geofencing & Geotargeting, IT Security, Maps, Security, Trade Finance, Trading Bots, Web3, SQLModel, Network Architecture, Networking, Mobile Architecture, Location Services, Auditing, Chromium, Railway, Cloud Architecture, Data Architecture, System Architecture, Integration, Workflow Automation & System Integration, Dynamics CRM 365, Agentic RAG Systems, Machine Learning, RAG Architecture, GitHub Actions, AI Safety, AI Security, Cloud Security, Machine Learning Operations (MLOps), CORS, Domain-driven Design (DDD), Pub/Sub, Video Streaming, Google BigQuery, Google Chat, Google Document AI, Google Drive, PDF, Microsoft Dynamics Great Plains (GP) ERP, Telemetry, Real-time Data, Internet of Things (IoT), Digital Banking, Financial Services, Microfinancing, Support, Ad Campaigns, Ads, Airtable, Digital Campaigns, Google Cloud Platform, Podcasting, Financial Data, Quantitative Analysis, Financial Modeling, Quantitative Finance, Quantitative Modeling, Smart TV, MPEG-DASH, Video Players, App Store and Google Play releases, Google Play Store, Offline Data Synchronization, REST API integration, React Native with Expo (EAS Build and Update), camera and photo capture, offline-first local storage and sync (SQLite or WatermelonDB), signature capture, Audio Streaming, Encrypted Media Extensions (EME), Widevine, Natural Language Processing (NLP), Pgvector, Prompt Engineering, Recommendation Systems, Vector Search, Roku, Platform Engineering, Salesforce CLI, DNP3, Modbus Protocol, SCADA, Supervisory Control & Data Acquisition (SCADA), Marketplaces, CRM developer, CRM, Care CRM, TLDCRM, Data Strategy, Lending, Turborepo, Product Owner, Logistics, Shipping, Compliance, Applied Mathematics, Mathematics, SharePoint Online, ERP django, Enterprise Resource Planning (ERP), SOAP, SOC 2, Agentic AI Systems, AI Voice Agents, Chrome Extensions, Microsoft Graph API, Sharding, App Store, Healthtech, iOS Authentication, Cryptography, Decentralized Finance (DeFi), Geofencing, Geospatial Data, ART19, Marketing Campaigns, Health, HIPAA, Financial Data Analytics, Decision Support, Linear, Megaphone
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
Share your needs
Choose your talent
Start your risk-free talent trial
Top talent is in high demand.
Start hiring