Senior WordPress Backend Developer with over 11 years of professional experience, specializing in custom WordPress development, backend architecture, integrations, performance optimization, and complex data-driven solutions. Experienced in working with both large-scale WordPress environments and high-traffic websites, with a strong focus on practical problem solving, maintainable code, and reliable solutions.

Plamen Kostadinov

Senior WordPress Backend Developer with over 11 years of professional experience, specializing in custom WordPress development, backend architecture, integrations, performance optimization, and complex data-driven solutions. Experienced in working with both large-scale WordPress environments and high-traffic websites, with a strong focus on practical problem solving, maintainable code, and reliable solutions.

Available to hire

Senior WordPress Backend Developer with over 11 years of professional experience, specializing in custom WordPress development, backend architecture, integrations, performance optimization, and complex data-driven solutions. Experienced in working with both large-scale WordPress environments and high-traffic websites, with a strong focus on practical problem solving, maintainable code, and reliable solutions.

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Experience Level

Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Intermediate
Intermediate
Intermediate
Intermediate
Intermediate
Intermediate
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Language

Bulgarian
Fluent
English
Fluent

Work Experience

Freelance WordPress Developer at Freelance / Remote
January 1, 2026 - Present
Delivered short-term WordPress development and maintenance for multiple clients, including landing pages, third-party integrations, WooCommerce and Multisite changes, and lightweight Gutenberg blocks. Troubleshot and extended existing themes, plugins, and client-specific functionality across varied WordPress stacks.
Senior WordPress Backend Developer at IGAMING.COM LTD
July 1, 2025 - November 1, 2025
Supported a backend team handling a portfolio of ~9,000 independent WordPress sites. Re-engineered a multilingual API import pipeline by replacing an inefficient postmeta model with 6–8 custom SQL tables, including source/override handling, batched concurrent processing, and retry queues—reducing a full import from several hours to ~90 seconds. Built a monitoring plugin that used an external crawler to validate actual rendered frontend output across three unrelated internal plugins, detecting missing/duplicate dynamic content impacted by JavaScript, AJAX, and geolocation.
Senior WordPress Backend at IGaming.com Ltd
July 1, 2025 - November 30, 2025
Maintaining a large portfolio of websites, creating new features, and refactoring legacy code to improve stability and performance across multiple projects, with a focus on security and scalable architecture.
Senior WordPress Developer at iO Bulgaria
April 1, 2024 - July 1, 2025
Developed and maintained custom WordPress functionality across ~100 client projects, including high-traffic publishing sites and complex Multisite installations. Built and extended custom Gutenberg blocks using React-based editor components with dynamic PHP frontend rendering and nested parent/child block structures. Worked with Composer-managed immutable WordPress architecture and GitLab CI with atomic symlink-based deployments, troubleshooting production and deployment issues. Improved frontend tooling by consolidating duplicated pnpm configuration, working daily with Docker-based local environments and automated quality checks.
WordPress Developer at iO Bulgaria EOOD
April 1, 2024 - July 31, 2025
Building WordPress themes and plugins, performing maintenance, implementing Gutenberg blocks with native backend, and managing CI pipelines (GitLab) for automated deployments; configuring AWS/cloud front for hosting and delivering assets; guiding local development with shared tooling; mentoring juniors.
Senior WordPress Developer / Technical Website Owner / Marketing Operations at Tick42 / Glue42 / interop.io
July 1, 2019 - December 1, 2023
Owned the company’s WordPress websites end-to-end: backend architecture, hosting, security, deployments, performance, and technical implementation of marketing requirements. Led a full rebuild of Glue42.com, replacing a legacy Divi/20+ plugin setup with a custom Gutenberg-based WordPress platform using ACF and an internal abstraction layer for 30–50 reusable blocks. Managed the application stack on AWS EC2/RDS with Nginx and PHP-FPM, plus CloudFront, combining migration, caching, and cleanup to reduce multi-second loads to consistently sub-second delivery. Designed frontend build tooling (npm/Webpack) and helped establish automated deployments using Jenkins, Ansible, and rsync with environment-specific branches and predictable rollbacks. Expanded into marketing operations by implementing lead/analytics/CRM workflows across Gravity Forms, ActiveCampaign, Pipedrive, GTM, GA4, and later HubSpot configuration and HubSpot–Salesforce synchronization during the interop.io merger.
WordPress Developer / Marketing Operations at Tick42 / Glue42 / Interop.io
July 1, 2019 - December 31, 2023
Supported company websites as part of the marketing team, assisting with technical tasks, day-to-day marketing tech work, CRM migrations and tooling (Pipedrive, HubSpot, ActiveCampaign), and general site optimization.
Senior WordPress Developer at DevriX
September 1, 2018 - June 1, 2019
Developed and maintained custom WordPress functionality for high-traffic, advertising-driven publisher platforms. Built traffic-source-aware advertising and AJAX/infinite-scroll functionality with dynamic loading of content and ad placements, integrating multiple third-party advertising providers. Developed custom WordPress plugins and native admin functionality with structured PHP architecture using Composer autoloading and class-based design, working with metadata persistence, validation, and sanitization.
WordPress Developer at DevriX
September 1, 2018 - June 30, 2019
Outsourcing company focusing on building high-traffic websites; theme and plugin development, integrations with WooCommerce and Visual Builder, one-time imports via crawlers, payments integrations (PayPal, Stripe), Shopify familiarity, HTML/CSS/JS, Gutenberg blocks; code reviews and junior mentoring.
WordPress Backend Developer at 2create
October 1, 2013 - September 1, 2018
Contributed backend development across 250+ client websites in a high-volume agency environment, often acting as the sole backend developer within small project teams. Designed and implemented custom WordPress functionality including content architectures, WooCommerce solutions, multilingual and Multisite setups, integrations, migrations, and data imports. Contributed reusable functionality to Carbon Fields (company’s custom-fields framework later becoming open source), including new field types and extensions.
WordPress Backend Developer at Outsourcing company in Varna, Bulgaria
October 1, 2013 - September 1, 2018
Developed WordPress back-end solutions, built WooCommerce integrations, implemented custom crawlers, PayPal and Stripe payments integrations; server-side customization.
Packhouse - Intake QC; Farm Worker at East Scrynie Farm Carnoustie
June 1, 2012 - September 30, 2018
Hands-on farm work and intake quality control in a high-volume agricultural environment.
WordPress Backend Developer at 2Create Varna
June 1, 2012 - September 30, 2018
WordPress backend and site development for an outsourcing IT company; building themes, plugins, integrations with third-party services; server-side adjustments (PHP/MySQL) and collaboration with cross-functional teams.
Waiter at Hotel Metro Golden Sands
July 1, 2008 - September 30, 2008
Customer service and hospitality duties in a busy hotel setting.

Education

Bachelor's degree in Informatics at University of Economics - Varna
September 1, 2009 - May 1, 2013
Entrepreneurship and Management (Second degree professional qualification) at Varna Trade School 'Georgi Stoyanov Rakovski'
September 1, 2004 - May 1, 2009
Bachelor's degree in Informatics at University of Economics - Varna
September 1, 2009 - May 1, 2013
Entrepreneurship and Management at Varna Trade School
September 1, 2004 - May 1, 2009
Bachelor's Degree in Informatics at University of Economics – Varna, Faculty of Informatics
January 1, 2009 - January 1, 2013
Secondary vocational education (Level II professional qualification in Economics) at Varna Trade School “Georgi Stoikov Rakovski”, Varna
January 1, 2004 - January 1, 2009

Qualifications

Second degree professional qualification: Economist (Entrepreneurship and Management)
September 1, 2004 - May 1, 2009

Industry Experience

Software & Internet, Gaming, Media & Entertainment, Professional Services