Ervin Domonkos, Developer in Szeged, Hungary
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Ervin Domonkos

Verified Expert  in Engineering

WordPress Developer

Szeged, Hungary
Toptal Member Since
August 20, 2021

Ervin is the perfect match if you are looking for a WordPress plugin developer with 13+ years of experience. He creates custom plugins from scratch, develops add-ons for existing plugins, and builds bridges for plugins that don't communicate properly with each other. Ervin has completed 200+ projects on different platforms with a perfect 5/5 rating history and maintained a multi-language website for one of the biggest retail chains in the UK, with thousands of hourly visitors.


Swift Horse Marketing
JavaScript, WordPress, User Experience (UX), WordPress Plugins...
WordPress, PHP, MySQL, Slack, JavaScript, Gutenberg Editor, CSS, Plugins...
APIs, Balsamiq, CSS, Git, WordPress, User Experience (UX), WooCommerce, PHP...




Preferred Environment

PhpMyAdmin, Slack, WordPress, WooCommerce, Easy Digital Downloads, AffiliateWP, PHP, Gutenberg Editor, Plugins, TeamViewer

The most amazing...

...plugin I've developed is Checkout Navigator, which automates a website's sales process while saving time and increasing income.

Work Experience

Senior WordPress Developer

2020 - PRESENT
Swift Horse Marketing
  • Worked with this digital agency specialized in food blog sites when they face technical challenges and can't solve in-house or are low on capacity.
  • Built-up a complete membership website with them using well-known membership plugins and custom code.
  • Replicated an old plugin running on one of their client's sites and loading very slowly. The new version reduced the load time of the plugin to only a few milliseconds.
Technologies: JavaScript, WordPress, User Experience (UX), WordPress Plugins, WordPress Themes, PHP, CSS, MySQL, Membership Sites, Paid Memberships Pro (PMPro)

WordPress Expert

2017 - PRESENT
  • Finished 185 projects with a perfect 5/5 rating history.
  • Built two portal websites for specific audiences with membership plans, online recurring payments, and internal communication functions for logged-in users.
  • Learned important aspects of professional behavior and successful strategies as a freelancer.
Technologies: WordPress, PHP, MySQL, Slack, JavaScript, Gutenberg Editor, CSS, Plugins, jQuery, Git, APIs, WooCommerce, AffiliateWP

WordPress Developer

2011 - PRESENT
  • Developed a booking plugin for a passenger transportation company.
  • Designed and developed a full website for a travel blogger.
  • Wrote several WordPress plugins that were published to the WP Plugin repository.
  • Created a sales automation plugin for event organizers and event marketers.
Technologies: APIs, Balsamiq, CSS, Git, WordPress, User Experience (UX), WooCommerce, PHP, JavaScript, jQuery, WooCommerce Subscriptions 2

Technical Manager

2013 - 2016
Wholegrain Digital
  • Created a new blog site for a world-famous chef with fast site speeds and ease of use as the main focus.
  • Maintained a vast multi-language website for one of the biggest retail chains in the UK. Paid close attention to all the details as the website had thousands of visitors every hour.
  • Managed ad-hoc small teams inside the agency from the design phase until project delivery.
  • Participated in the agency and saw it grow from a 3-4-person micro-business to a 10-20-person small agency.
Technologies: WordPress, PHP, MySQL, JavaScript, CSS, Kanban, Slack, Balsamiq, Git

Checkout Navigator

A premium WordPress plugin that automates the sales process of event organizers, training sessions, and consulting businesses. I was the project owner completing all the development with occasional help in design and marketing by contractors. The project involved coding integration with several popular APIs, writing Gutenberg blocks, creating a complex plugin settings page, and setting up a complete license management system behind it.

The Wandering Wordsmith

A full website built using WordPress and Gutenberg blocks for a travel blogger and writer. A challenge in the project was that we had to unify two previously separate websites to make the new site more powerful in terms of SEO. The new site received a fresh new look that aligned with the client's personality and message.

Time Zone Fix for Events Calendar Plugin
A worldwide learning platform client used The Events Calendar (TEC) plugin for managing their online events. However, the TEC plugin always showed the start and end times to its users in a pre-set time zone. The client wanted to show all events in the local time zones of the users.

The solution was an add-on plugin that detected and saved the user's time zone to their account using geolocation (with minimal user interaction to keep the UX smooth). It then calculated the event start times based on the difference between the event's and the user's time zone.

Recipe Membership Network Maintenance
I maintained a network of websites that consisted of a food blog and several membership websites built around it. The work involved regular updates, backups, bug fixes, connecting the sites with external services, and adding new functionalities to the site.

The project's real challenge was the high number of users, so I had to do all updates with the least possible downtime and outside the site's rush hours. Concerning the latter, it was helpful that we were in different time zones with the client.

Plan Successful Websites

I wrote a book about planning websites (in the Hungarian language, but planning to get it translated to English, too).
The book was written for website owners and taught them how to write professional briefs (so-called "Complete Website Plans") for their web developers.
I had to write this book because, during my career, I've seen a lot of stories when projects weren't ready on time or needed more costs than necessary-mostly because the communication wasn't crystal clear between the client and the developer.
With a "Complete Website Plans"-that is understandable by both parties-the development route can be smoother, and costs can be kept at a manageable level.

WordPress Plugin Framework-TPL-FW
TPL-FW is an options framework that can speed up plugin development as it makes it easy for the developer to create settings pages and post meta boxes within plugins.
This plugin framework works similarly to ACF, but it can be built into plugins as a library in a white-label way. So with TPL-FW, you don't have to rely on other plugins to have a complex system of settings for your WordPress plugin.

License Management for WooCommerce

The client needed a system that managed license keys sold by their WooCommerce shop. They couldn't find an out-of-the-box solution, so they outsourced it-I coded it as a WooCommerce add-on plugin.
My plugin provided an API for external websites, too-that could query if the license key in question exists or not and if it is already activated or not.

Shipping Cost Calculator for Building Material Store
The client approached me because he was stuck setting up the correct calculation for shipping costs in his WooCommerce-based building material webshop.
He was already using a plugin for advanced shipping calculation, but it was not enough. His shipping costs were based on more factors that the plugin could handle: ZIP code, weight, size, number of pallets needed, and others.
My task was to write an add-on for this plugin that extended its functionality to fulfill the store's all shipping calculation needs.

Healthcare Portal for Practitioners and Patients

The goal was to create a community website that allowed nutritional therapy practitioners and their patients to communicate, keep consultations, and collect patient data via intake forms.
The challenging part of the project was that the site had to be HIPAA compliant.

Real Estate API Connection

My task with this real estate website was to connect it with a real estate database API and load data of different listings into its pages dynamically. Users were able to set various search criteria, and the API call happened based on this user-entered data.

Speed Optimization of a Real Estate Site

Before the optimization, the site was loading slowly (home page: 3-4s, listings page: 10+s). I did the regular optimizations for the whole website (caching, minifications, image optimization) that reduced loading times significantly. For the listings page, I had to write a custom caching function, as it was especially database-intensive. In the end, the site was loading in around 1s on desktops.
2003 - 2009

Master's Degree in Small Business Development

University of Szeged - Szeged, Hungary

1998 - 2002

High School Diploma in Software Technology

Korosy J. Technical School - Szeged, Hungary


jQuery, Stripe API, WordPress API, Braintree API, Social Media APIs, Nightwatch.js, WooCommerce API, Stripe, React, Node.js, BuddyPress


PhpMyAdmin, Gutenberg Editor, Balsamiq, Advanced Custom Fields (ACF), Balsamiq Mockups, Slack, AffiliateWP, Git, Mailchimp, Stripe Checkout, TeamViewer, LearnDash


PHP, JavaScript, CSS, Less, HTML, HTML5


WordPress, WooCommerce, Twilio


MySQL, Amazon S3 (AWS S3)


Kanban, Management, Object-oriented Programming (OOP)




Plugins, Web Development, Programming, Themes, HTML5 Geolocation, WordPress Plugins, WordPress Themes, WooCommerce Subscriptions 2, Subscriptions, Membership Sites, Paid Memberships Pro (PMPro), MemberPress, Website Maintenance, User Flows, Web Usability, Usability Guidelines, User Experience (UX), Gravity Forms, Easy Digital Downloads, APIs, Geolocation Detection, Usability, TinyMCE, Shipping, Calculators, Site Speed Optimization, Page Speed Optimization, Business, Web Marketing, Internet Protocols, User Needs, Usability Engineering, Google SEO, Video Chat, WP Rocket, SSH

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