Available to hire
I’m John Moscarillo, a Principal Full-stack Engineer specializing in AI-powered web platforms, prompt engineering, and end-to-end system design. I help clients integrate large language models into production, define data ingestion and embedding strategies, and build scalable UI architectures and component libraries that accelerate product delivery. My work blends hands-on engineering with strong UX thinking to deliver performant, user-centered web experiences.
Over the past decade I’ve co-founded Recipe to Kitchen, led frontend and full-stack efforts for WX Now and Nexus at Qumulo, and delivered enterprise-grade web apps for Premise Data, Vaisala, and 3TIER. I thrive on building robust codebases, scalable UI libraries, and data-driven interfaces, while collaborating closely with product, design, and research teams to turn complex requirements into delightful, reliable products.
Skills
Experience Level
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Language
English
Fluent
Work Experience
Principal Full-stack Engineer at Designing Webs, Inc
March 1, 2025 - PresentAdvised clients on end-to-end integration of large language models into web platforms including prompt engineering and deployment best practices. Designed and implemented advanced retrieval-augmented generation (RAG) pipelines for Renewable Energy and Mental Health domains. Defined data ingestion workflows, embedding strategies, and vector database schemas to support high-precision knowledge retrieval and contextual generation.
Staff Front-end Engineer at Designing Webs, Inc
March 1, 2025 - August 15, 2025Executed enhancements for the core web UI integrating legacy and modern JavaScript frameworks. Established the Qumulo Component Library, a foundational UI component repository using TypeScript, React, Tailwind, Recharts, and D3. Led architecture and UI implementation for "Nexus" using Next.js, TypeScript, React, and AWS services. Implemented continuous deployment workflows with GitHub Actions.
Principal Front-end & Full-stack Engineer at Designing Webs, Inc
April 30, 2023 - August 15, 2025Spearheaded architecture and development of a responsive single-page application with progressive web features for WX Now. Engineered and deployed mobile ports for iOS and Android providing native-like experience. Led design of interactive, responsive web interfaces balancing user-centric design with technical constraints.
Software Engineer at Qumulo
January 1, 2024 - August 15, 2025Built dynamic UIs using React and Recharts. Integrated Mapbox for advanced mapping visualizations. Developed scalable backends with Remix and Express supporting file tile servers.
Senior Front-end Engineer at Premise Data
December 31, 2022 - August 15, 2025Developed new features for web applications using React and Flow. Collaborated with product and design teams to engineer new customer portal with React, Typescript, Hapi.js, and Cube.js hosted on Google Cloud Platform. Built GitHub CI/CD workflows.
Senior Software Engineer, Senior UX and Product Designer at Designing Webs, Inc (Vaisala)
September 30, 2022 - August 15, 2025Designed and developed map-based interfaces driven by multiple microservices using React, Redux, and Typescript. Defined user personas and use cases. Iterated with users and stakeholders using sketches, whiteboard sessions, and high-fidelity mockups. Integrated new JavaScript frontends with legacy backends.
Director of User Experience at 3TIER, Inc. - Vaisala
December 31, 2015 - August 15, 2025Enhanced and managed customer and internal software applications. Maintained strong user advocacy through communication with customers and stakeholders. Utilized personas, use cases, usability testing, and heuristic analysis to inform product decisions.
Director of Web Engineering at 3TIER, Inc. - Vaisala
December 31, 2020 - August 15, 2025Created and maintained team roadmap delivering company dashboard aligned with goals and budgets. Bridged product management and development resolving issues early. Incorporated design into agile development and produced award-winning product enhancing 3TIER's industry presence and aiding funding acquisition. Winner of 2009 AWEA Commercial Achievement Award.
Software Development Engineer at Microsoft Corporation - Sidebar Gadgets
December 31, 2007 - August 15, 2025Designed and developed default operating system sidebar gadgets for Windows Vista and 7. Collaborated daily with interdisciplinary teams. Defined code standards for default gadgets. Developed internationalized, accessible HTML, CSS, and JavaScript compliant with OS standards.
Lead Developer at Foote, Cone & Belding (FCBi Seattle)
December 31, 2006 - August 15, 2025Executed online initiatives under tight advertising agency timelines. Collaborated with creative executives, account execs, and graphic designers delivering projects on time and budget. Successful projects included HP Works, HP PurchasEdge, and HP SureSupply through focus groups, usability testing, SEO, and partner relationship building.
Lead Web Developer at JDA Advertising
December 31, 2001 - August 15, 2025Executed all online initiatives, communicating continually with creative, account, and design teams. Delivered projects on time and budget within rigorous ad agency timelines. Served clients such as @Home Networks, Avid Technology, IBM, Novell, and Red Hat Software.
Principal Full-stack Engineer at Designing Webs, Inc
March 1, 2025 - PresentAI Consulting & RAG System Development: Advising clients on end-to-end integration of large language models into web platforms, including prompt engineering and deployment best practices. Designed and implemented retrieval-augmented generation (RAG) pipelines tailored to Renewable Energy and Mental Health domains. Defined data ingestion workflows, embedding strategies, and vector database schemas supporting high-precision knowledge retrieval and contextual generation.
Staff Front-end Engineer at Designing Webs, Inc
March 1, 2025 - September 16, 2025Nexus UI engineering: Led architecture and implementation of the core web UI for Nexus; established the Qumulo Component Library (QCL) and modern design system; implemented CI/CD pipelines with GitHub Actions; used TypeScript, Next.js, React, Tailwind, Recharts, and D3; integrated Mapbox/visualizations and backend services.
Principal Front-end & Full-stack Engineer WX Now at Designing Webs, Inc
April 1, 2023 - September 16, 2025Spearheaded architecture and development of a responsive SPA with progressive web features; deployed mobile ports to iOS App Store and Google Play; led in-house design of interactive, responsive web interfaces.
Senior Front-end Engineer at Qumulo
January 31, 2024 - September 16, 2025Built dynamic UIs using React and Recharts, integrated Mapbox for advanced mapping visualizations; developed scalable backends with Remix and Express to support rich frontend features; worked on GFS tile servers.
Senior Front-end Engineer at Premise Data
December 31, 2022 - September 16, 2025Developed new features for the customer portal using React, TypeScript, Hapi.js, and Cube.js; hosted on Google Cloud Platform; collaborated with product teams; built GitHub Actions-based CI/CD.
Senior Software Engineer, Senior UX and Product Designer at Vaisala
September 30, 2022 - September 16, 2025Designed and developed two map-based interfaces driven by multiple microservices using React, Redux, and TypeScript; defined user personas and use cases; produced high-fidelity mockups and iterative user feedback.
Director of Web Engineering at 3TIER, Inc.
December 31, 2009 - September 16, 2025Created and maintained roadmap, bridging product management and software development; integrated design process with agile workflow; delivered an award-winning product on time to support funding.
Director of User Experience at 3TIER, Inc.
December 31, 2015 - September 16, 2025Led user research and design strategy, incorporating personas, use cases, journey studies, usability testing and heuristic analysis to guide product decisions.
Director of Web Engineering at 3TIER, Inc. / Vaisala
December 31, 2020 - September 16, 2025Directed web engineering initiatives; aligned product development with user insights; drove a multi-year roadmap for internal and external dashboards.
Software Development Engineer, Sidebar Gadgets at Microsoft Corporation
December 31, 2007 - September 16, 2025Designed and developed Windows Vista/7 sidebar gadgets; collaborated with cross-functional teams to define code standards and ensure accessibility and internationalization.
Lead Developer at Foote, Cone & Belding (FCB)
December 31, 2006 - September 16, 2025Led online initiatives for major campaigns; managed cross-functional teams; delivered on time and within budget for HP and other clients.
Lead Web Developer at JDA Advertising
December 31, 2001 - September 16, 2025Directed online initiatives for a portfolio of clients; ensured timely delivery and client satisfaction.
Principal Full-stack Engineer AI Consulting & RAG System Development at Designing Webs, Inc
March 1, 2025 - PresentAdvising clients on end-to-end integration of large language models into web platforms, including prompt engineering and deployment best practices. Designed and implemented retrieval-augmented generation (RAG) pipelines tailored to Renewable Energy and Mental Health domains. Defined data ingestion workflows, embedding strategies, and vector database schemas supporting high-precision knowledge retrieval and contextual generation.
Staff Front-end Engineer at Qumulo (Nexus)
March 1, 2025 - September 16, 2025Executed enhancements for the core web UI, established the Qumulo Component Library (QCL), and led the UI for Nexus using TypeScript, Next.js, React, and the QCL. Implemented CI/CD workflows with GitHub Actions and integrated back-end services (AWS Timestream, PostgreSQL).
Principal Front-end & Full-stack Engineer at WX Now
April 1, 2023 - September 16, 2025Spearheaded architecture and development of a responsive SPA with progressive web features. Led mobile porting for native-like experiences and designed interactive, user-centric interfaces. Integrated Instacart API and leveraged LLMs for data ingestion, parsing, and dynamic content generation.
Senior Front-end Engineer at Qumulo
January 31, 2024 - September 16, 2025Built dynamic UIs with React and Recharts; integrated Mapbox visualizations; developed scalable backends with Remix and Express to support rich frontend features.
Senior Front-end Engineer at Premise Data
December 31, 2022 - September 16, 2025Developed features for the customer portal using React and TypeScript; collaborated across product and design teams; implemented GitHub Actions CI/CD workflows.
Senior Software Engineer, Senior UX and Product Designer at Vaisala
September 30, 2022 - September 16, 2025Designed map-based interfaces driven by microservices; defined personas and use cases; iterated with users and stakeholders using high-fidelity mockups; ensured UI alignment with business goals.
Director of User Experience at 3TIER, Inc.
December 31, 2015 - September 16, 2025Enhanced and managed customer and internal software applications; integrated user research into product decisions; maintained a user-centered roadmap.
Director of Web Engineering at 3TIER, Inc. / Vaisala
December 31, 2009 - September 16, 2025Bridged product management and software development; integrated design processes with agile workflows; delivered timely, user-tested dashboards and interfaces.
Software Development Engineer at Microsoft Corporation
December 31, 2007 - September 16, 2025Designed and developed Windows Sidebar Gadgets; collaborated across design, PM, and test teams; defined code standards and ensured accessibility and internationalization.
Lead Developer at Foote, Cone & Belding
December 31, 2006 - September 16, 2025Led online initiatives for major brands; focused on usability, SEO, and on-time delivery; contributed to high-profile HP campaigns with research-backed design.
Lead Web Developer at JDA Advertising
December 31, 2001 - September 16, 2025Delivered online advertising initiatives; collaborated with creatives and account teams; consistently met timelines and budgets for client campaigns.
Education
Bachelor of Arts at University of Colorado, Boulder, CO
January 11, 2030 - August 15, 2025Associate Degree at Art Institute of Colorado, Denver, CO
January 11, 2030 - August 15, 2025Bachelor of Arts at University of Colorado, Boulder
January 11, 2030 - September 16, 2025Associate Degree at Art Institute of Colorado, Denver
January 11, 2030 - September 16, 2025Bachelor of Arts at University of Colorado, Boulder
January 11, 2030 - September 16, 2025Associate Degree at Art Institute of Colorado, Denver
January 11, 2030 - September 16, 2025Qualifications
Industry Experience
Software & Internet, Energy & Utilities, Healthcare, Retail, Media & Entertainment, Professional Services, Education, Other
Skills
Experience Level
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Hire a Web Developer
We have the best web developer experts on Twine. Hire a web developer in Seattle today.