Stefan Barrett

Stefan Barrett CTO VISA: Japan Permanent Resident (Nationality: British) A Tokyo, Japan PROFILE Experienced technical leader with 20+ years building and scaling systems across desktop, web, and cloud-native platforms. Proven track record of delivering high-impact solutions—from solo greenfield builds to large-scale, multi-team systems—emphasizing reliability, performance, and maintainability. Strong hands-on background in full-stack development, distributed systems, and cloud infrastructure (Azure, GCP). Skilled in technical architecture, CI/CD automation, and leading engineering teams through complex design and implementation challenges. Driving AI integration including prompt engineering & ai agents. Experienced in mentoring developers, driving engineering best practices, and aligning solutions with product goals. SKILLS & ABILITIES • Development – 20+ years with C# (.NET Framework 1.0–4.8.1, .NET Core 3.1–9.0), SQL Server (10+ years), plus some experience with Solidity, Java, C/C++, Python, MongoDB & Docker. • Cloud & DevOps – 7+ years Azure, 1 year GCP; CI/CD pipelines • Tools: Visual Studio, Visual Studio Code, Cursor, Eclipse, GitHub, Confluence, JIRA, Azure DevOps • AI: ChatGPT integration & prompt engineering. API integration. Agentic AI in Microsoft ecosystem. • Data & Reporting – Power BI, Excel, VBA; building dashboards and data pipelines • Tools & Methodologies – Agile (Scrum, Kanban), Git, CI/CD, automated testing • Technical Architecture – Lead architect for all AgUnity client deliveries over the past 6 years, • People Development – Mentoring engineers, developing team culture, onboarding, and continuous improvement • Project Management – Planning, execution, costing, and reporting using JIRA, Azure DevOps, MS Project, Confluence, and Excel • Team Leadership – 15+ years managing 1–20 people across 1–5 cross-functional teams; hiring, performance reviews, and team structuring. • Client & Stakeholder Engagement – Pre-sales, delivery, and post-support; translating technical concepts for non-technical execs and clients; issue scoping, costing, and resolution EXPERIENCE AgUnity, Tokyo CTO (June) 2019 – Present Led the design and implementation of end-to-end client solutions, translating business requirements into robust, scalable systems. Took ownership of technical scoping, architecture, and hands-on development across the full SDLC, including CI/CD, testing, and post-deployment support. Architected and deployed Azure-based infrastructure, ensuring high availability, security, and performance. Designed core backend systems and data pipelines with a focus on scalability, maintainability, and cloud-native best practices. Contributed to engineering standards by introducing code review processes, CI/CD automation, and technical mentoring, fostering a strong developer culture across globally distributed teams. Key Projects & Wins • Hub - a SaaS solution for managing farmer & transactional data, having web & mobile components with a ChatGPT addon. It supports millions of farmers being onboarded and helped to win multiple contracts. • Fresh food tracking - capturing data from IoT devices for near real-time location & temperature tracking, with backend rules engine for alerting & location resolution. Running 24/7. • AgriUT - Website & infrastructure (C#, SQL Server, Solidity) to allow purchase & rewarding of a blockchain token (ERC20) for rewarding 1000s of farmers. • SaaS Client application - used to track millions of dollars flowing to organizations running projects in more than 70 countries. Client was so impressed they gave us 3 more contracts. • Banking integration - allowing Vanilla farmers in PNG to be paid directly into their bank accounts, reducing fraud & non-payment scenarios. Identified bad data within local organizations (25%). Nomura Securities, Tokyo Vice President, Global Markets IT 2008 (October)– 2019 (June) Worked on a diverse portfolio of projects, ranging from independently managed initiatives to large-scale global engagements, serving as the Asia Technical Lead, driving strategic technical solutions and ensuring successful project delivery. Key Projects & Wins • Web site for showing Nomura Research to 20,000+ external (global) customers. Tech Lead for 4 devs, and Project lead. Replaced the previous unpopular tool and cleaned up more than 10,000 customers records, resulting in greater clarity to the business regarding their research. • Application to retrieve information on client clearing from JSCC & reconcile with internal systems. Creating portfolios of trades from failed members for bidding. Regulatory requirement. • Internal facing global application for traders & salespeople to input cash & derivative trades. Covering both pre-trade (MiFID2) & post-trade for risk analysis. Asia IT tech lead for small team. • Monitoring tool which monitored & aggregated internet-based market sources and presented them to the Japanese traders. Removed requirement for trader to manually check & freeing up more time for trading. • Japan HR application to track sick leave & holidays, for 1000+ users. Lehman Brothers Ltd., (Tokyo & London) Senior Analyst Developer (Japan) - Research Analyst (Europe) - Delivered analytics and trading technology solutions across mortgage and fixed income businesses in Europe and Asia. Transferred to Japan to provide development expertise, following the success of earlier projects in Europe. Key Projects & Wins • Commercial Mortgage Validation (Japan) – Led enhancements to validation processes, reducing manual workload for financial staff by 20+ hours per month. • Mortgage Analytics Platform (Europe) – Architected and implemented a system to analyze and track mortgage asset pools, integrating external data sources (Experian credit scores, mortgage originator feeds, internet-based sources, and a data warehouse). Processed 200,000+ loans daily across multiple jurisdictions. • Predictive Modeling (Europe → Japan) – Implemented analytical models, including sub-prime predictive risk analysis, reducing analytics turnaround time by 50%. Successful adoption led to rollout in Japan. Misys (Risk), London Team Lead / .NET Architect 1999 – 2005                 Progressed from developer to lead architect for a financial risk analysis platform used by tier 2–3 banks. Led a distributed team of 8+ developers across India and England, delivering multiple UI releases and contributing to the architectural direction of the product suite. Earlier career Various software roles spanning financial and labeling industries. Qualifications June/2025Agentic AI Solution Architecture — Participant 2005 – 2006MCTS (3 Microsoft exams) and MCPD (2 exams) 2002MCAD (3 Microsoft exams on Windows & Web based Applications and XML Web Services and Server Components with Microsoft .NET) 28/1/2000MCP (Designing & Implementing Desktop Applications with MS Visual basic) 1992 – 1994Nottingham-Trent University   BSc (Hons) Computing Systems