Mariusz Panek

Web Developer with over 16 years of experience, specializing in comprehensive development, optimization, and maintenance of websites and e-commerce platforms. As a freelancer operating under the brand Codelarix, I’ve been delivering projects since July 2023 — creating custom modules, extensions, and templates for WordPress, PrestaShop, and proprietary CMSs. My approach combines robust back-end solutions with efficient front-end code, always focused on user experience and business results.

Technologies & Tools

My main programming language is PHP, with broad compatibility (from version 5.4 to 8.4). I use quality control tools like PHPStan, PHP_CodeSniffer, syntax testing, and PHPDoc to ensure the code remains clean, scalable, and easy to maintain. Modules and libraries are managed with Composer.

I run projects in Docker containers, ensuring consistency across development environments and simplifying migrations and team collaboration. For version control, I use Git with GitHub Actions to automate unit testing, static analysis, and CI/CD deployments.

Backend & Databases

I mainly work with MariaDB/MySQL for data handling. I design and optimize database structures — reducing unnecessary joins, indexing properly, and refactoring SQL queries to improve the loading times of dynamic pages. I use performance analysis tools like EXPLAIN to identify and eliminate bottlenecks.

Frontend & UX

I develop modern, responsive templates using HTML5, CSS3, and JavaScript (including jQuery). I ensure cross-browser compatibility and optimize the critical rendering path. Techniques like CSS/JS minification, lazy loading for images, and font preloading are used to boost performance.

Accessibility (WCAG), SEO & Performance

I conduct dedicated audits using tools like Pa11y and Seonaut, adapting code to WCAG 2.1 AA standards (headings, alt tags, contrast, keyboard navigation, ARIA roles).

SEO optimization includes proper meta tags, schema.org, sitemaps, robots.txt, correct HTTP/HTTPS redirections, and integration with Google Search Console / GA4.

Selected Projects Codelarix

• Modern PrestaShop e-commerce store: reduced TTFB from ~800ms to ~200ms, implemented payment modules and SEO-friendly breadcrumbs, dynamic ESI blocks with Varnish cache.
• Functional WordPress extensions: PDF generators for product/category pages, custom post types, courier API integrations.
• Legacy migration & refactoring: upgraded projects to PHP 8.4, removed deprecated functions, ensured PSR-12 compliance.

My Work Philosophy

• Automation-first: Docker + GitHub Actions + static testing = faster iterations without regressions.
• Code quality: code reviews, static analysis, and full PSR & OWASP compliance.
• Performance focus: backend efficiency, lightweight front-end, layered caching (Redis, Varnish).
• Accessibility & SEO: compliant with legal standards (WCAG) and Google best practices — leading to better UX and rankings.

I’ve completed hundreds of projects, delivered dozens of custom modules and optimized e-commerce stores. I focus on quality, scalability, and client satisfaction.