John Castellese
Senior WordPress & Front-End Developer
Professional Summary
Senior WordPress and front-end developer with 15+ years of web development experience, including deep experience building, maintaining, optimizing, and extending complex WordPress platforms across agency, enterprise, and news media environments.
Strong background in PHP, modern JavaScript, accessibility, performance optimization, high-fidelity design implementation, and collaborative engineering workflows. Experienced in translating business, marketing, content, and design requirements into maintainable technical systems.
Recently focused on AI-assisted engineering workflows that improve planning, debugging, documentation, and delivery speed.
What I'm Especially Good At
I'm strongest where design, content, business needs, and engineering overlap. I'm used to taking ambiguous requirements, legacy constraints, and high-fidelity design goals and turning them into maintainable WordPress and front-end systems.
Complex WordPress platforms
Custom themes, plugins, blocks, editorial workflows, multilingual content, and long-term maintainability.
Design-to-code execution
High-fidelity interfaces that preserve design intent while staying accessible, responsive, and maintainable.
Production problem solving
Performance issues, migrations, redirects, broken links, CMS cleanup, integrations, and legacy remediation.
Modern engineering workflow
AI-assisted development, documentation, code review, automation, and practical process improvement.
Technical Expertise
Core Technologies
- JavaScript (ES6+)
- PHP (WordPress ecosystem)
- HTML
- CSS (modern layout & architecture)
Frameworks & Libraries
- React (WordPress blocks/FSE)
- Vue
- AngularJS
- Next.js
- jQuery
- GSAP
- Three.js
WordPress Platform Engineering
- Custom themes & plugins
- Block/FSE development & custom blocks
- WordPress multisite
- Multilingual implementations
- REST API integrations
- Data imports/exports & migrations
- Performance optimization & technical SEO remediation
- Long-term site maintenance
Front-End Engineering
- UI systems & modular JavaScript patterns
- Accessibility-driven development
- Responsive, component-based layout systems
- Performance optimization
- Interactive and animated interfaces
- Design integration & creative implementation
Hosting & Deployment
Pantheon · WPEngine · Flywheel · Vercel · AWS · Supabase · Cloudflare
Tools & Workflow
Git · GitHub · VS Code · Chrome DevTools · WP-CLI · Postman · Node.js/npm · Vite/Webpack · Composer · Pantheon · Cloudflare
Testing & diagnostics: Lighthouse · Axe DevTools · Query Monitor · Jest · Vitest · Xcode/Simulator · BrowserStack
AI-assisted development: Cursor · ChatGPT · Claude
Automation & integrations: n8n · Zapier · Google APIs · HubSpot · Salesforce
Experience & Leadership
Senior Developer
- Lead developer on client projects across nonprofit, education, technology, and bioscience sectors.
- Delivered custom interfaces for eCommerce systems, membership platforms, and complex workflow applications.
- Developed highly customized WordPress solutions using modern JavaScript, PHP, and API integrations.
- Implemented AI-assisted development and automation tools, improving project delivery speed by ~30%.
- Built performant, accessible front-ends integrating deeply with CMS and backend systems.
- Partnered closely with design, content, and client teams to translate creative vision into maintainable, scalable code.
Development Operations Manager
- Oversaw front-end development and operations across multiple high-profile entertainment and automotive accounts.
- Delivered highly interactive web experiences for globally recognized entertainment and automotive brands, including interactive marketing microsites and creative web applications.
- Built product customization interfaces for automotive programs, involving animated transitions and synchronized UI/UX state changes.
- Developed interactive marketing microsites for internationally known artists, translating high-concept creative direction into responsive, expressive web experiences.
- Worked with animation frameworks (GSAP) and custom transition systems to create engaging user interfaces.
- Led UI/UX development initiatives ensuring design consistency, accessibility, and performance while pushing creative boundaries.
- Coordinated technical teams, refined workflows, and introduced version control and code review standards.
- Served as creative engineering liaison between design, motion teams, and technical leads to implement high-fidelity interactive concepts under tight launch timelines.
Front-End Developer
- Handled front-end development, site management, and feature planning for a high-traffic news platform.
- Produced layout systems, ad templates, and editorial tools for the internal CMS.
- Trained staff and maintained technical documentation.
Web Developer
- Designed and built client websites, e-commerce pages, and internal dashboards.
- Maintained brand consistency and accessibility across digital properties.
Web Developer
- Created promotional and editorial websites supporting multiple publications.
- Coordinated with designers and editors to maintain accuracy and style alignment.
Selected Projects & Activities
Client Projects
A selection of recent client work completed as part of my role at Three Seven, highlighting projects where I served as lead developer or primary contributor.
Remake Learning Days: National Education Festival
- Primary developer for the multi-state event platform across 5+ festival seasons
- Implemented custom event filtering, scheduling, and multi-region content systems
- Built a scalable, high-traffic WordPress architecture serving thousands of events
- Integrated modern block patterns and performance enhancements over successive years
- Collaborated with regional teams to improve editorial workflows and UX
Deque Systems: Corporate Website
- Served as long-term lead developer for Deque's corporate WordPress platform, supporting multiple major site iterations, WordPress upgrades, production enhancements, and ongoing maintenance over more than six years.
- Built, maintained, and extended custom WordPress themes, blocks, front-end components, editorial workflows, and integration points, with a focus on accessibility and content team usability.
- Worked closely with Deque stakeholders and agency team members to scope technical work, plan releases, troubleshoot production issues, and translate marketing, content, accessibility, and business requirements into practical WordPress solutions.
- Because Deque is a recognized accessibility industry leader, the work required a particularly high standard for accessibility.
axe-con: Global Digital Accessibility Conference
- Architected and developed the WordPress site powering Deque's annual axe-con conference
- Built custom block-based templates for schedules, speakers, and session content
- Optimized for high-traffic registration surges during conference windows
- Ensured WCAG-compliant front-end, responsive layouts, and inclusive UX
- Designed the theme for multi-year reuse with rapid configuration
Arbor Assays: Biosciences eCommerce Platform
- Primary developer for Arbor Assays' WordPress/WooCommerce-based product and assay catalog
- Implemented custom eCommerce functionality for scientific product variations, datasheets, and ordering workflows
- Built reusable block components and optimized product detail templates for clarity and performance
- Enhanced UX for researchers with improved product search, filtering, and documentation access
- Collaborated closely with the Arbor Assays leadership team to modernize infrastructure and maintain long-term reliability
ThermoAnalytics: Corporate Website
- Led development for the recent launch of ThermoAnalytics' corporate WordPress website, supporting a complex B2B technology brand with product, solution, service, resource, and industry content.
- Built custom WordPress templates, blocks, front-end components, and content structures to support reusable page-building patterns, maintainable implementation, and editor-friendly workflows.
- Worked with design, strategy, content, and project management teams to translate technical subject matter into a polished, responsive, production-ready marketing site.
Modelon: Corporate Website
- Served as lead developer for Modelon's corporate WordPress platform through 2024, supporting a technical B2B software brand with product, industry, resource, and international marketing content.
- Worked on a WordPress multisite and multilingual implementation using MultilingualPress, building custom templates, content structures, front-end components, and editorial workflows for localized site experiences.
- Supported ongoing marketing enhancements, including content offer landing pages, conversion-focused page iterations, A/B testing support, campaign updates, and reusable components, with attention to maintainability, performance, SEO considerations, and content team usability.
Professional Initiatives
- WordPress Platform Modernization. Maintained and improved complex WordPress sites through custom theme/plugin development, migrations, data restructuring, performance remediation, technical SEO cleanup, and editor-facing improvements.
- Integrated generative AI tools into agency development processes
- Built MCP services connecting Google Drive and Monday.com APIs
- Custom WordPress blocks and full site editing templates in React
- Specialize in design-to-code integration, translating complex creative concepts into pixel-perfect, maintainable implementations
- Led standards compliance and optimization initiatives for high-profile accessibility clients
- Worked across diverse industry sectors: Entertainment & Media, Automotive, Technology & Biosciences, Nonprofit & Education
Education
Grand Valley State University
Emphasis in Printmaking and Graphic Design. Coursework in design systems, typography, and digital production. Established a foundation for front-end development and UI design.