Kostiantyn I.

⚡Need help building, customizing, or fixing a WordPress or WooCommerce website? I work with Elementor, custom PHP, plugins, API integrations, and performance optimization. From new website development and everyday improvements to complex custom functionality, I can handle it all. I'm a senior WordPress developer with experience since 2011. Top Rated | 100% Job Success | $600K+ earned | 18,000+ Upwork hours | 400+ completed jobs. **CUSTOM WORDPRESS DEVELOPMENT** - Custom WordPress plugin development, themes, PHP hooks and filters - Advanced Custom Fields (ACF), custom post types, reusable templates, and custom functionality - WordPress theme customization, plugin conflicts, PHP errors, and complex bug fixing **WOOCOMMERCE DEVELOPMENT** - WooCommerce checkout customization and payment functionality - Custom product logic, pricing, and WooCommerce plugin development - Membership and paid-content functionality - Inventory, product, and order synchronization with external systems **REST API & THIRD-PARTY INTEGRATIONS** - WordPress REST API, webhooks, and third-party API integrations - CRM, warehouse, and external product/order systems - Custom PHP/MySQL backend logic, data processing, and integration troubleshooting **WORDPRESS SPEED & PERFORMANCE** - WordPress speed optimization and Core Web Vitals - PageSpeed Insights, database queries, and plugin performance troubleshooting - PHP compatibility, technical fixes, and ongoing WordPress maintenance - WordPress migration, safe updates, and staging-based testing **ADDITIONAL WORDPRESS EXPERIENCE** - LearnDash and WooCommerce eLearning and membership platforms - Multilingual WordPress websites and Hebrew RTL layouts - Content-heavy publishing websites and structured CMS workflows **SELECTED PROJECT EXPERIENCE** - Client-verified custom WooCommerce plugin development - WooCommerce checkout customization and warehouse API synchronization - WordPress eLearning platforms with LearnDash and paid course access - Custom WordPress websites and documented PageSpeed results **HOW I WORK** I review the existing codebase before making changes, identify technical risks, and test updates before deployment whenever the environment allows. Whether you need a specific bug fixed, new custom functionality, an API integration, or ongoing WordPress/WooCommerce development, I can help. ⭐Share your website URL and what you need built, fixed, or improved. I'll suggest a practical next step. **ADDITIONAL DEVELOPMENT EXPERIENCE** Beyond custom WordPress and WooCommerce development, I also work with: - **Website Builders & Frontend:** Elementor, Webflow, Figma to WordPress, PSD to WordPress, responsive web design, HTML, CSS, JavaScript. - **Payments & eCommerce:** WooCommerce store setup, payment gateway integrations, Stripe, PayPal, subscriptions, and membership functionality. - **Migration & Maintenance:** WordPress migration, CMS migration, hosting transfers, WordPress maintenance, and bug fixing. - **SEO & Performance:** Technical SEO, Core Web Vitals, GTmetrix, website performance optimization, and WordPress speed optimization. - **Backend & Integrations:** Custom PHP, WordPress plugins, custom themes, REST API, third-party integrations, and database functionality.