Sebastian Welcome's you!
Full Stack Engineer specializing in accessible, enterprise-grade web applications. I bring 5+ years of experience across nuclear, automotive, healthcare, and fintech — building Angular, React, and .NET systems that are fast, inclusive, and built to last. Currently focused on WCAG 2.1/2.2 compliance and accessibility-first architecture at Authentic Digital.
About Me
I'm a Full Stack Engineer with 5+ years of experience building enterprise-grade web applications across some of the most demanding industries in the world — nuclear energy, autonomous vehicles, healthcare, and fintech. Today, I channel that foundation into my specialization: accessible, inclusive digital experiences that work for every user.
At Authentic Digital, I build Angular applications with a strong commitment to WCAG 2.1/2.2 and ADA compliance — designing reusable component systems with full keyboard navigation, semantic HTML, and screen reader support, and conducting accessibility audits with WCAG, Lighthouse, and NVDA. Accessibility isn't a checkbox for me; it's a core engineering discipline.
Before that, at Westinghouse Nuclear, I built secure, high-performance Angular and .NET systems under strict regulatory requirements — an environment that sharpened my instincts for correctness, compliance, and maintainability. That experience, combined with earlier work on React platforms for Optum and real-time data tools for Aptiv's autonomous vehicle division, gives me a rare breadth across the stack and across industries.
I thrive at the intersection of technical precision and user empathy — writing clean, testable code while keeping real users at the center of every decision. I collaborate closely with UX/UI designers, QA, and business stakeholders to translate requirements into interfaces that are not just functional, but genuinely usable by everyone.
If you're looking for a full stack engineerwho brings enterprise discipline, accessibility expertise, and cross-industry perspective to every project — let's talk.
Experience
Front End Engineer at Authentic Digital • Jun 2025 - Present
Build accessible, high-performance Angular applications with a strong focus on WCAG 2.1/2.2 and ADA compliance. Design and implement reusable UI component systems with full keyboard navigation, semantic HTML, and screen reader compatibility. Conduct accessibility audits using axe DevTools, Lighthouse, and NVDA, write automated tests for accessibility and UI reliability, and champion accessibility-first practices across enterprise-level frontend architectures.
Full Stack Engineer at Westinghouse Nuclear • Aug 2024 - Feb 2026
Built and maintained secure, high-performance Angular and .NET applications for the nuclear energy sector. Designed RESTful APIs, optimized database queries, and enhanced system performance under strict regulatory and compliance requirements. Managed concurrent projects under tight deadlines while driving continuous improvement through emerging technologies.
Freelance Developer & Medical Studies • Oct 2022 - Jun 2024
Delivered client-focused web development projects while concurrently pursuing medical studies — sharpening analytical thinking, rapid domain learning, and the ability to context-switch across high-stakes disciplines.
Front End Engineer at Rumble Fish Development (Contractor for Optum) • May 2021 - Oct 2022
Developed and maintained customer-facing React applications using TypeScript, Redux, and Material UI for a large-scale healthcare platform. Built reusable component libraries in a monorepo, improved accessibility and UI/UX compliance, led code reviews, and implemented automated testing pipelines for high-quality, reliable delivery.
Full Stack Engineer at Aptiv • Sep 2020 - May 2021
Contributed to an autonomous vehicle data validation platform, developing high-performance web applications for real-time processing of camera, radar, and LiDAR sensor data. Delivered cross-platform solutions with robust performance and user-focused design in a safety-critical engineering environment.
Front End Developer at Spinney • Aug 2019 - Jan 2020
Built responsive, high-conversion user interfaces with React, Redux, and Node.js for a fast-growing fintech startup. Integrated NoSQL databases and delivered scalable, revenue-driving solutions that supported rapid business growth.
Case Studies
Platforms and products I've helped build across industries — from nuclear energy to fintech.
Authentic Digital
Front End Engineer
Feb 2026 – Present
Building enterprise Angular applications for institutional fund managers overseeing some of the largest ETF portfolios in the market, with a strong focus on WCAG 2.1/2.2 accessibility, ADA compliance, and enterprise-grade UI systems.
- ETF portfolio dashboards and fund analytics for institutional managers
- WCAG 2.1/2.2 and ADA accessibility compliance across the platform
- Enterprise UI component system with full keyboard and screen reader support
Westinghouse Nuclear
Full Stack Engineer
Aug 2024 – Feb 2026
Built and maintained secure, high-performance applications for one of the world's leading nuclear energy companies — reactor inspection tools, laboratory systems, and regulatory compliance platforms.
- Reactor inspection and condition-monitoring dashboards
- Nuclear laboratory management and reporting systems
- Strict regulatory compliance, audit trails, and security controls
Optum — Connect Your Care
Front End Engineer
May 2021 – Oct 2022
Developed and maintained customer-facing React applications for Connect Your Care — the largest HSA and insurance-management platform in the US, serving millions of plan members.
- Shared component library inside a large-scale monorepo
- WCAG accessibility compliance improvements across the platform
- Automated testing pipelines for reliable, high-quality delivery
Aptiv
Full Stack Engineer
Sep 2020 – May 2021
Contributed to a safety-critical AV data validation platform, building high-performance dashboards for real-time processing and visualisation of camera, radar, and LiDAR sensor feeds.
- Real-time sensor dashboards for camera, radar, and LiDAR data streams
- Automated data-validation pipelines with anomaly-flagging UIs
- Cross-platform performance tuning for safety-critical workflows
Spinney
Front End Developer
Aug 2019 – Jan 2020
Built responsive, high-conversion interfaces for a fast-growing mobile gambling platform — real-time betting UIs, game lobbies, and in-app payment flows serving thousands of concurrent users.
- Real-time betting interfaces with live odds and scoreboard updates
- In-app payment, KYC verification, and account management flows
- Mobile-first responsive design optimised for low-latency interaction
Skills & Tools
With 5+ years of professional experience across frontend, backend, and full-stack development, I've worked with a wide range of languages, frameworks, and tooling — from Angular and React to .NET and Node.js — in enterprise environments that demand precision and reliability.
My current focus is on accessibility engineering: building WCAG 2.1/2.2-compliant interfaces, auditing with tools like axe DevTools and NVDA, and establishing accessibility-first standards across teams. I stay current with emerging standards and continuously invest in deepening my technical toolkit.