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Viktor Fonic
Verified Expert in Engineering
Shopify Customizations Developer
Split, Croatia
Toptal member since August 19, 2013
Bio
Viktor is an eCommerce developer with over 10 years of experience designing, building, and scaling full-stack webshops and apps. He has a proven track record of delivering enterprise-grade solutions at Microsoft, and he owns end-to-end project lifecycles as a sole engineer. From solving page load performance challenges to leading and mentoring teams aligned with business goals, Viktor combines deep technical expertise with leadership and communication skills to drive measurable business impact.
Portfolio
Meillart
Ruby on Rails (RoR), JavaScript, TypeScript, GraphQL, Hasura, PostgreSQL...
Radio Depot
Shopify, Liquid, JavaScript, HTML, CSS, Front-end, User Experience (UX)...
Pilestone
Shopify, JavaScript, HTML, CSS, Front-end, User Experience (UX)...
Experience
- Ruby on Rails (RoR) - 11 years
- Shopify Plus - 10 years
- Shopify Customizations - 10 years
- User Experience (UX) - 10 years
- JavaScript - 10 years
- Shopify - 8 years
- React - 8 years
- Custom Shopify Apps - 7 years
Preferred Environment
GitHub, Cursor AI, User Experience (UX), Shopify Plus, Ruby on Rails (RoR)
The most amazing...
...thing I've developed is an app that diagnoses patients and offers treatments based on their symptoms and medical history.
Work Experience
Project Tech Lead | Full-stack Developer
2020 - PRESENT
Meillart
- Guided the client from zero to one from day one of the project. The client was so happy that he offered me the position of CTO.
- Expanded the original Shopify webshop project into a marketplace.
- Wrote various automation scripts for communication between company staff, vendors, and customers.
Technologies: Ruby on Rails (RoR), JavaScript, TypeScript, GraphQL, Hasura, PostgreSQL, DigitalOcean, Heroku, Shopify, Shopify API, Shopify Plus, Liquid, Front-end, Startups, User Experience (UX), User Interface (UI), Shopify Liquid, HubSpot, SQL, Docker
Shopify Expert | Full-stack developer
2020 - 2021
Radio Depot
- Developed effective site structure and product selection.
- Optimized page speed loading times to improve user experience.
- Worked on creating a unique customer portal with customer preferences saved for faster repetition of orders and configuration of bought products.
Technologies: Shopify, Liquid, JavaScript, HTML, CSS, Front-end, User Experience (UX), User Interface (UI), Shopify Liquid
Shopify Expert | Full-stack Developer
2020 - 2020
Pilestone
- Researched color-blindness issues to develop a competitive color-blindness test.
- Developed color-blindness test following the most credible method for testing color-blindness.
- Organized several email campaigns for potential customers who fill-in the color-blindness test.
Technologies: Shopify, JavaScript, HTML, CSS, Front-end, User Experience (UX), User Interface (UI), Shopify Liquid
Shopify App Developer
2017 - 2019
AllNet Apps
- Built a common, shared codebase framework to reuse across all apps.
- Since the launch, both apps have had exclusively 5-star reviews.
- Continued working on the shared framework to build additional apps rapidly.
Technologies: JavaScript, Shopify API, Ruby on Rails (RoR), Ruby, Shopify, Shopify Customizations, HTML, Liquid, Shopify Theme, Custom Shopify Apps, Next.js, Tailwind CSS, Shopify Design, eCommerce, GraphQL, Front-end, Startups, User Experience (UX), User Interface (UI), Shopify Liquid, SQL
Full-stack Software Developer
2017 - 2017
CivicLift
- Implemented long tasks running in the background.
- Created recurring events schedules and management.
- Increased database performance.
- Built drag-n-drop management of homepage blocks.
- Implemented reusable search components and used them to search and filter multiple types of records.
Technologies: MongoDB, Meteor, React, HTML, GraphQL, Figma, Front-end, Startups, User Experience (UX), User Interface (UI), SQL, Docker
Shopify Developer
2017 - 2017
TopGlas GmbH
- Completely rewrote the shop's main selling point, Konfigurator, to use a more modern state machine pattern (similar to Redux).
- Developed a page composer tool that transforms Shopify store CMS functionality into a drag-n-drop interface for building-block style construction of shop pages.
- Optimized JS and CSS delivery, which reduced page size and increased page download speeds by ~50%.
- Improved "Add to cart" speed by 6x.
- Implemented custom user click tracking.
- Implemented user account pages where the user can manage orders, addresses, and other account information.
- Performed SEO audits.
Technologies: Liquid, Shopify, JavaScript, SCSS, HTML, Shopify Customizations, Shopify Theme, Custom Shopify Apps, Shopify Plus, Tailwind CSS, Shopify Design, eCommerce, GraphQL, Figma, Front-end, User Experience (UX), User Interface (UI), Shopify Liquid
Shopify Developer
2016 - 2016
Sitar s.r.l.
- Built a new Shopify experience from the ground up.
- Migrated existing shop data from the old PrestaShop installation.
- Integrated a subscriptions app with "unsupported" QuickView - made it work.
Technologies: Liquid, Shopify, JavaScript, SCSS, HTML, Shopify Customizations, Shopify Theme, Shopify Design, eCommerce, Front-end, User Experience (UX), User Interface (UI), Shopify Liquid, SQL
Full-stack Ruby on Rails Developer
2015 - 2016
DVELP, Ltd.
- Rebuilt the sign-up flow into a single-page multi-step React form that saw a 5x increase in conversion.
- Introduced React and Redux technologies to the company.
- Wrote an open-source SEO plugin for Ruby on Rails apps.
- Introduced a Shopify theme development template for faster theme development.
- Built several custom Ruby on Rails apps from the ground up.
Technologies: PostgreSQL, Heroku, RSpec, Redux, React, Ruby on Rails (RoR), Ruby, Shopify, Shopify Customizations, HTML, Liquid, Shopify Theme, Shopify Plus, Shopify Design, eCommerce, Front-end, User Experience (UX), User Interface (UI), Shopify Liquid, SQL
Software Engineer
2014 - 2015
Microsoft Ireland R&D
- Integrated a TypeScript testing framework into the build system to improve development reliability.
- Implemented a website redesign that increased the number of installs by over 5% (+20,000 users).
- Worked on the organization of a company-wide hackathon (120,000 employees, more than 100 hackathon projects, worldwide event).
- Nominated as employee of the year after the first ten months of employment.
Technologies: jQuery, JavaScript, TypeScript, C#, HTML, Front-end, User Experience (UX), User Interface (UI), SQL
Full-stack Ruby on Rails Developer
2013 - 2013
Music Delta
- Reduced the number of database queries by 80%.
- Implemented a sustainable authorization system.
- Fixed security issues and other various bugs.
- Completely rewrote the administration interface, improving speed, usability, and security.
- Added application monitoring.
Technologies: Ruby on Rails (RoR), HTML, Front-end, SQL
Full-stack Ruby on Rails Developer
2012 - 2013
Do the Life
- Developed a highly scalable solution for generating user schedules with a heuristic algorithm.
- Integrated the Ruby on Rails application with a Java worker to improve the algorithm's performance.
- Implemented a natural language parser, allowing users to describe events in natural language.
- Implemented a tutorial/website tour for first-time login and introduction to new features.
- Handled cross-time zone event synchronization.
- Implemented a "Coming Soon" landing page with user sign-up.
- Implemented a cron process to handle recurring jobs with periodic execution.
Technologies: Ruby on Rails (RoR), HTML, Front-end, User Interface (UI), SQL
Software Developer
2010 - 2013
Sitar s.r.l.
- Developed several custom-made pharmaceutical applications to perform diagnosis predictions.
- Created a specific user-management application for managing user licenses.
- Gained experience working with a foreign client.
- Implemented a completely automatic update system with no need for user action when new data or application versions were made available.
- Created specific database management application for pharmacists to insert data with a single click.
- Built a dynamic GUI with vector graphics to function appropriately across all screen resolutions.
Technologies: Java, User Experience (UX), User Interface (UI), SQL
Software Developer
2011 - 2011
Netgen d.o.o.
- Created an API to integrate the ShoutEm platform with eZ Publish CMS.
- Worked with eZ Publish CMS internals for better tailoring of content to ShoutEm users.
- Gained significant experience with the eZ Publish CMS and ShoutEm API.
Technologies: JavaScript, PHP, HTML, Front-end, User Experience (UX), User Interface (UI)
Experience
Do The Life
Do The Life is a Ruby on Rails virtual secretary web application.
GitHub Account
https://github.com/vfonicA collection of code samples and contributions to open-source projects.
Liceknjiga
https://github.com/vfonic/liceknjigaLiceknjiga is a Ruby on Rails social network for sharing photos with privacy, likes, comments, and friends functionality. For more information, see http://liceknjiga.herokuapp.com/.
Todolist
https://github.com/vfonic/Angular-Devise-TodolistA TODO application which demonstrates how one might connect AngularJS with a Ruby on Rails back-end for authentication and usage. Additionally, includes an API for mobile application access.
Water Logic
Solution for pouring water game for web, cross-compiled to JS from C++ with Emscripten.
Code: https://github.com/vfonic/water_logic
Website: http://vfonic.github.io/water_logic/
Code: https://github.com/vfonic/water_logic
Website: http://vfonic.github.io/water_logic/
Education
2011 - 2013
Master's Degree in Computer Science
University of Zagreb - Zagreb, Croatia
2007 - 2011
Bachelor's Degree in Software Engineering
University of Zagreb - Zagreb, Croatia
2009 - 2010
Bachelor's Degree in Software Engineering
University of Maribor - Maribor, Slovenia
Skills
Libraries/APIs
Liquid, React, Shopify API, Chai, jQuery
Tools
RSpec, Mocha, Shopify Plus, Figma, Sublime Text, Git, GitHub
Languages
HTML, JavaScript, Sass, GraphQL, Shopify Liquid, SQL, PHP, Java, C#, TypeScript, Ruby, SCSS, CSS
Frameworks
ZURB Foundation, Jasmine, Redux, Bootstrap, Ruby on Rails (RoR), Next.js, Tailwind CSS
Paradigms
Agile Software Development
Platforms
Meteor, Shopify, Heroku, WordPress, HubSpot, Docker, MacOS, Visual Studio Code (VS Code), DigitalOcean
Storage
MongoDB, PostgreSQL, Hasura
Other
Apps, Shopify Customizations, Shopify Theme, Custom Shopify Apps, Shopify Design, eCommerce, Front-end, Startups, User Experience (UX), Cursor AI, User Interface (UI), AI Assistants, Machine Learning
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