
Julien Cousin
Verified Expert in Engineering
WordPress Developer
Annecy, France
Toptal member since May 3, 2022
Julien is a senior WordPress and full-stack developer with 10+ years of experience, specializing in complex, high-performance projects. He has managed 300+ high-traffic WordPress sites with individual sites ranging from 300,000 to over 2 million monthly visitors, handling major traffic peaks during events like the World Cup. Julien specializes in custom WooCommerce, Node.js, React, Docker, Gutenberg, and API integrations.
Portfolio
Experience
- WooCommerce - 10 years
- PHP - 10 years
- WordPress - 10 years
- WordPress Plugins - 10 years
- WordPress Themes - 10 years
- Search Engine Optimization (SEO) - 8 years
- Site Speed Optimization - 7 years
- Elementor - 5 years
Preferred Environment
PHP, Sass, HTML, CSS, jQuery, WordPress, WooCommerce, Web Development
The most amazing...
...project I built was The Lilypad, a 17,000+ product digital marketplace migrated to WooCommerce, featuring a custom billing system and advanced promotion engine.
Work Experience
Full-stack Developer
Freelance
- Migrated the Lilypad marketplace (17,000+ digital products) from X-Cart to WooCommerce, building a custom multi-vendor billing system and advanced promotion engine with rules by vendor, product, and category.
- Developed a complete insurance platform for Swiss Global Insurance from scratch, including a simulator, online subscription funnel, and back-office CRM for claims, secure document uploads, and automated workflows.
- Rebuilt the ISIT Paris and Sofiprotéol websites using Sage and Symphony for a Paris agency, ensuring full WCAG AA compliance, W3C validation, and eco-friendly high-performance design with custom Gutenberg blocks.
- Rebuilt The Green Lab, a Swiss multilingual WooCommerce store, through full code cleanup, design overhaul, FR/EN/DE translation harmonization, and technical SEO optimization for sustained growth.
- Built a complete learning management system for 3 Hour Roadway Safety using Tutor LMS, automating the full funnel from enrollment and payment to training completion and certificate generation.
- Designed and developed custom Gutenberg blocks and patterns using ACF across multiple client projects, enabling editorial teams to create dynamic, reusable content without technical intervention.
- Built a fully automated cryptocurrency trading platform for CryptoLoco, integrating API connections to major exchanges, real-time trading dashboards, and automated strategy execution logic.
- Replaced an Elementor-heavy design with a custom theme for LawyerSorted, improving performance and maintainability while preserving the original design fidelity and UX consistency.
WordPress Tech Lead
North Star Network
- Led technical management of 300+ high-traffic WordPress sites across the media group, with individual sites ranging from 300,000 to over 2 million monthly visitors and major peaks during World Cup events.
- Migrated the entire portfolio to a modern infrastructure using Docker and Bedrock, industrializing deployments and standardizing development environments across 300+ sites.
- Managed and mentored a team of 4 developers, establishing Git workflows, code reviews, and technical task distribution to ensure scalable delivery across the portfolio.
- Developed custom WordPress plugins for the SEO team, including hreflang management, rich snippets, and structured data schemas to improve technical SEO across all sites.
- Built a comprehensive library of custom Gutenberg blocks with ACF, enabling editorial teams to compose dynamic, reusable content autonomously without developer intervention.
- Optimized Core Web Vitals across 300+ sites through advanced caching strategies, CDN integration, and server-level optimizations, maintaining green scores under multi-million monthly traffic loads.
Senior WordPress Developer
North Star Network
- Developed and customized WordPress themes and plugins tailored to editorial teams' needs across multiple brands, including Mundo Deportivo, Football Whispers, and Top Mercato.
- Built custom SEO plugins (hreflang management, rich snippets, structured schemas) to improve technical SEO and international visibility across the media portfolio.
- Implemented advanced Gutenberg blocks with ACF to simplify content management and give editorial teams greater flexibility when composing dynamic articles.
- Optimized Core Web Vitals through advanced caching strategies, database query optimization, and CDN integration to sustain high-traffic performance at scale.
- Collaborated closely with SEO and marketing teams to improve technical site structure, maximize search visibility, and align development with business objectives.
- Used WordPress, PHP, Advanced Custom Fields (ACF), Gutenberg, Sage, Core Web Vitals, Performance Optimization, JavaScript, WordPress Theme Development, WordPress Plugin Development, Amazon Bedrock.
Senior WordPress Developer
Digitalize Me
- Developed a complete WordPress insurance platform from scratch for Swiss Global Insurance, integrating a quote simulator, online subscription funnel, and back-office CRM for policy and claims management.
- Built a full-stack inventory management system in Node.js and React for El Septimo, featuring automated low-stock alerts and real-time synchronization with the WooCommerce storefront.
- Customized WooCommerce for My Swiss Apple with an advanced product variation selector, dynamic color filtering, and a custom vacation mode system for automated customer notifications.
- Led eCommerce performance optimizations using WP Rocket and Cloudflare, significantly reducing load times and improving Core Web Vitals across multiple high-traffic WooCommerce sites.
- Developed a secure document management system for insurance claims, enabling encrypted uploads, payment tracking, and automated follow-ups with client notifications.
- Mentored and supervised 4 junior developers and interns, conducting code reviews, onboarding, and establishing development standards to ensure consistent project quality.
- Developed a custom internal CRM tool on WordPress for the agency's client management, streamlining onboarding, billing, and project tracking across the team.
Senior WordPress Developer
MyCodedMind
- Developed a custom WooCommerce eCommerce platform for the Ecuadorian market, integrating Uber as a shipping method, a pioneering approach for last-mile delivery in local eCommerce at that time.
- Built a custom internal tool for the marketing team, designers, and clients to collaborate on social media planning and content scheduling, streamlining the content production and approval workflow.
- Maintained and upgraded a portfolio of client WordPress websites, handling PHP upgrades, plugin and theme updates, and establishing automated backup workflows for reliable disaster recovery.
- Developed custom WordPress websites from Figma and Sketch mockups for agency clients, implementing pixel-perfect integrations with responsive design and optimized performance.
- Established version control workflows using GitLab and task tracking using YouTrack, improving team collaboration and project delivery across the agency's client portfolio.
Senior WordPress Developer
Ekorp
- Developed custom WordPress websites for agency clients using an internal custom MVC system, building pages, content, and structures without relying on templates or page builders.
- Integrated subscription systems in Node.js and React into multiple client projects, delivering full-stack features aligned with agency standards and client requirements.
- Delivered a custom institutional website for Groupe Morneau, a long-established logistics transport company, building the entire architecture without template or builder dependencies.
- Developed the Republica Cultura cultural gazette website, which was later presented to the Minister of Culture and Heritage of Ecuador as a showcase for the agency's work.
- Maintained and optimized performance across the agency's client portfolio, handling updates, bug fixes, and deployment workflows to ensure long-term site stability.
Experience
Tech Lead WordPress — 300+ High-traffic Media Sites
https://footballwhispers.comThe challenge was to maintain performance, SEO, and scalability across a large media portfolio with significant traffic spikes, while industrializing deployments and leading a team of developers.
Key contributions:
• Migrated the infrastructure to Docker and Bedrock for standardized deployments
• Developed custom SEO plugins (hreflang, rich snippets, schemas) for the SEO team
• Built custom Gutenberg blocks with ACF for editorial autonomy
• Continuously optimized Core Web Vitals (caching, CDN, lazy loading)
• Led a team of 4 developers
Results: 300+ sites stabilized and industrialized, Core Web Vitals in green across the portfolio, multi-million monthly traffic handled with stability.
Sites: Mundo Deportivo (US/LATAM), Football Whispers, Top Mercato, Afrik-Foot.
UK Legal Marketplace: Custom Theme, WooCommerce Subscriptions & Per-contact Payments
https://lawyersorted.com/The challenge was to modernize a heavy Elementor-based setup into a custom, maintainable theme while building a dual monetization model: recurring subscriptions for law firms and per-contact micro-payments for end users.
Key contributions:
• Replaced Elementor setup with a custom theme built from a Figma design, improving performance and maintainability
• Built WooCommerce payment workflows for law firm subscriptions and per-contact fees
• Developed a dynamic contact system with booking customizations and improved search filters
• Ensured full responsiveness and cross-browser compatibility
• Integrated Trustpilot and Google Reviews for law firm profiles
• Optimized performance with WP Rocket and Cloudflare, and handled SEO improvements
• Configured automated email notifications and enhanced user dashboards
Results: Modernized marketplace with custom design, reduced technical debt, and a scalable monetization system.
Custom Insurance Platform with Full Back-office CRM
https://swissglobalinsurance.comThe challenge was to build a corporate website and a business tool in a single WordPress platform, without page builders, with complex insurance logic and automated workflows for claims and subscription management.
Key contributions:
• Developed a custom WordPress theme from scratch, bypassing the need for page builders.
• Designed a quote simulator with conditional logic and real-time premium calculation.
• Built a full back-office CRM for subscription management, client tracking, and secure document uploads.
• Implemented an automated claims workflow covering upload, validation, payment, and notifications.
• Established advanced lead and status management within the WordPress admin.
Results: Corporate site and business tool unified in one platform, full autonomy for the insurance team on case handling, and GDPR compliance with secure document management.
B2B eCommerce for Industrial Sanitary Fittings (1,000+ Products, 5+ Variations Each)
https://sanitaryfittings.us/The challenge was to migrate the site to a more maintainable setup and empower the client to manage a complex product catalog autonomously, while preserving performance and scalability.
Key contributions:
• Migrated the full site to Divi and customized it to match the client's branding and functional requirements
• Designed scalable product templates for 1,000+ items with multiple variations each, ensuring a seamless browsing and purchasing experience
• Configured Divi tools and dynamic templates to give the client full autonomy over product management
• Provided ongoing maintenance, ensuring optimal performance and compatibility with WooCommerce and theme updates
Results: Client-autonomous B2B eCommerce handling 1,000+ products with variations, and stable long-term performance.
Advanced WooCommerce: Variation Selector & Custom Vacation Mode
https://myswissapple.chThe challenge was to build a smooth shopping experience on a complex variation catalog, and to handle owner absences without losing customers.
Key contributions:
• Developed an advanced WooCommerce variation selector with dynamic color filtering.
• Implemented multi-level e-commerce filters for enhanced catalog navigation.
• Created a custom "vacation mode" with automatic customer notifications about delivery delays.
• Optimized performance using WP Rocket and Cloudflare.
• Integrated payment and stock management systems.
Results: Smooth product experience on a complex catalog, reduced cart abandonment due to variation confusion, and business continuity ensured even during owner absences.
Premium Institutional Websites on Sage/Symphony (WCAG Compliant)
https://www.sofiproteol.com/The challenge was to integrate Adobe XD mockups while meeting strict requirements: WCAG AA accessibility compliance, eco-design principles, and full editorial autonomy through a custom Gutenberg blocks library.
Key contributions:
-Used Sage (Laravel) with Symphony for integrating Adobe XD mockups into modern, maintainable code.
• Built WordPress themes from scratch without page builders, based on Adobe XD designs.
• Developed a comprehensive library of custom Gutenberg blocks for autonomous editorial composition.
• Ensured full WCAG AA compliance and W3C validation.
• Adopted an eco-design approach, optimizing page weight and minimizing resources.
Results: Two institutional sites delivered with full WCAG and W3C compliance, editorial teams fully autonomous on content composition via Gutenberg, and exemplary performance and accessibility metrics.
STNY Rentals, Saint Agnes Residence, and Saint Joseph’s Immigrant Home
https://www.saintjosephsimmigranthome.com/Initially managed as three separate websites, the project focused on consolidating them into a single WordPress multisite installation. This migration aimed to streamline maintenance and updates while ensuring consistent branding and user experience across all sites. The designs were kept simple and clean, leveraging custom Gutenberg blocks for easy content management.
MY ROLE
• Migrated three individual websites into a unified WordPress multisite setup, simplifying maintenance and reducing operational complexity.
• Designed and developed custom Gutenberg blocks to create flexible and editable layouts for each site.
• Ensured the seamless migration of content and functionality while maintaining consistency across the sites.
• Performed testing and optimization to guarantee responsiveness and usability across devices and browsers.
Premium E-commerce + Inventory App (WooCommerce + Node.js/React)
https://el-septimo.ch/The challenge was to build a premium eCommerce with zone-based shipping calculations, alongside an internal inventory tool replacing the team's manual Excel spreadsheets.
eCommerce work:
• WooCommerce customized for premium positioning
• Dynamic shipping cost calculation by customer location
• Real-time stock synchronization between storefront and back-office
• Secure payment integrations
Inventory app (Node.js/React):
• Full-stack inventory management tool
• Automated low-stock alerts and reorder notifications
• Simplified UI for non-technical daily use
• WooCommerce synchronization
Results: Premium eCommerce live and operational, internal tool replacing manual Excel workflows, and real-time stock visibility for the team.
eCommerce Marketplace Migration: X-Cart to WooCommerce (17,000+ Products)
The challenge was to migrate a large product catalog without SEO loss, while building a custom billing engine and promotion system tailored to multi-vendor marketplace requirements.
Key contributions:
• Full catalog migration from X-Cart to WooCommerce with SEO and URL preservation
• Custom billing system for vendor commission management
• Advanced promotion engine with rules by vendor, product, or category
• Wishlist integration and comprehensive coupon management
• Kadence theme customization and Core Web Vitals optimization on a large catalog
Results: 17,000+ products successfully migrated without SEO regression, fully functional multi-vendor marketplace with autonomous management by the client, and performance maintained despite high volume.
eCommerce Takeover & Full Redesign (Multilingual Swiss WooCommerce)
https://thegreenlab.chThe mission was to rebuild the site without starting from scratch: clean up the technical debt, redesign the interface, harmonize translations, and optimize SEO while maintaining business continuity.
Key contributions:
• Conducted a full technical audit and code cleanup, removing unnecessary plugins and performing refactoring.
• Executed a complete design overhaul to restore consistent brand identity.
• Achieved multilingual harmonization across French, English, and German with thorough translation restructuring.
• Implemented technical SEO optimization, including refining URLs, metadata, schema markup, and sitemaps.
• Enhanced performance through caching, image optimization, and improvement of Core Web Vitals.
Result: Clean, stable, maintainable site with fully restored multilingual consistency.
LMS Platform with Tutor LMS: Online Training & Certification
https://3hourroadwaysafety.comThe primary challenge was to create a fully automated funnel encompassing enrollment, payment, training, and automatic certification, complete with progress tracking, quizzes, and certificate generation.
Key Contributions:
• Set up and customized Tutor LMS to align with specific business rules.
• Integrated the payment funnel with WooCommerce and established access management.
• Enabled learner progress tracking across modules, quizzes, and final scores.
• Implemented automatic certificate generation upon successful course completion.
• Designed the UX to ensure a seamless learning journey.
Results: Fully autonomous and scalable training platform, 100% automated purchase-to-certification funnel, and client fully autonomous on pedagogical content management.
Education
Professional Degree in Software Development
Institute Jaume Balmes - Barcelona, Spain
Skills
Libraries/APIs
jQuery, WordPress API, WooCommerce API, Google API, Google Maps, REST APIs, Stripe, React, Node.js, Binance API, Auth0 API, Facebook Ads API, Facebook API, Sage
Tools
ACF PRO, Gutenberg Editor, Figma, Advanced Custom Fields (ACF), Stripe Checkout, Google Analytics, Figma to Webflow, Wix, Adobe Lightroom, Seos, Git, Tutor LMS
Languages
PHP, HTML, CSS, JavaScript, HTML5, PHP 8, Sass, Python
Frameworks
Bootstrap, Chrome, Divi, Bedrock, Laravel
Platforms
WordPress, WooCommerce, Firefox, Safari, Amazon Web Services (AWS), Docker
Paradigms
Responsive Web Design (RWD), Search Engine Optimization (SEO), UI Design
Storage
MySQL, PostgreSQL
Industry Expertise
Web Design, E-learning
Other
Web Development, WordPress Plugins, WordPress Themes, Responsive Design, Online Payments, eCommerce, Ajax, Full-stack, APIs, Reviews, HTML to WordPress, WordPress eCommerce, FTP, Forms, Pop-ups, Front-end, Elementor Pro, Bug Fixes, Maintenance, Upgrades, Data Migration, WordPress Migration, WordPress Design, Elementor, Gravity Forms, Yoast SEO, PayPal, Site Speed Optimization, Caching, Cloudflare, Symphony, Payment APIs, Webhooks, Performance, Design, Web Accessibility, Web UX, SEO Tools, Page Speed Optimization, WP Rocket, Google Tag Manager, Learning Management Systems (LMS), WordPress SEO, API Integration, WordPress Multisite, Web Hosting, Performance Optimization, Core Web Vitals, User Experience (UX), User Interface (UI), Google SEO, Optimization, General Data Protection Regulation (GDPR), Web Security, Drag & Drop, WPMU DEV, Security
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