Krzysztof Zdunkowski

I have worked with PHP since version 4.2, on both small websites and larger business applications, using custom solutions as well as Laravel, Yii and KohanaPHP. I have worked through successive language releases including PHP 8.4. My responsibilities have also included technology selection, application architecture and the basic technical assumptions of projects.

A large part of my work has involved performance optimisation in both new and existing systems. I have used debugging and profiling tools such as Xdebug and analysed complete solutions rather than PHP in isolation — including database queries and server configuration.

iFotos was another practical example: PHP handled metadata while Nginx served files via X-Accel-Redirect, helping keep infrastructure cost and resource use low.

I have used Laravel on projects ranging from small services to larger business applications. I built Blade views and REST APIs documented with Swagger, created Artisan commands for automation and used queues for asynchronous work.

I implemented JWT-based authentication and user-account workflows including registration, login, password reset and e-mail confirmation. Redis was used to cache data whose retrieval placed the highest load on the application and database.

I have used Yii for simple CRUD applications as well as larger business systems. I worked with ActiveRecord, schema migrations and Gii and created reusable components and widgets used across multiple parts of an application.

I built paginated REST APIs, console commands and RBAC-based permissions and used Redis for heavier queries. Tables, filtering, pagination and reporting were recurring areas where reusable components substantially reduced duplicated work.

I have worked with MySQL both when designing new databases and optimising existing systems. My work includes schemas, data types, indexes including covering indexes, and solutions using GIS and JSON data. I have experience with MySQL 5.x and 8.x.

I have worked with autocommit as well as explicit START / COMMIT / ROLLBACK, and with deadlock analysis under isolation levels including READ COMMITTED and REPEATABLE READ.

I have also handled backups and recovery with mysqldump and phpMyAdmin and configured users, roles and permissions.

I have worked with Nginx since version 0.7, using it for HTTP(S), reverse proxying and caching static assets in both small services and distributed environments.

I configured traffic distribution using least_conn and ip_hash, and used limit_req_zone and limit_conn_zone to control overload and traffic spikes. Earlier deployments also included HTTP/2 configuration and http2_push_preload.

In iFotos, X-Accel-Redirect allowed PHP to prepare metadata and counters while Nginx handled the actual file transfer.

I have mainly used Redis for expensive query results, frequently accessed data and sessions, reducing database calls and application response time.

I select TTL values with the trade-off between freshness, database load and memory consumption in mind. I used this pattern in Laravel and Yii-based applications.

I have most often worked with existing Docker images and Compose configurations, using them to launch complete PHP-FPM, Nginx, Redis and MySQL environments.

I understand Dockerfile structure, networks, volumes and multi-service Compose setups as well as image optimisation, multi-stage builds and private registries. In projects, Docker has primarily been a practical environment and deployment tool.

I have worked with JavaScript since before jQuery, writing both plain-JS scripts and larger modular SPA-style applications. I have also worked with frontend frameworks and maintained Node.js code.

I understand prototypes, hoisting, the event loop and asynchronous behaviour and pay attention to how code structure affects browser memory use. For example, defining separate functions on each object instance instead of sharing methods through a prototype can become significant at scale.

Node.js is not my preferred platform, but I have maintained and refactored it, including PM2-managed modules with monitoring and alerts.

I adopted Vue later than JavaScript itself, but quickly found the component model productive. Commercially I built individual views and more substantial components, including a reusable REST-paginated table supporting pagination headers and different column data types.

I also worked on an administration panel using Vue 3, Nuxt and TypeScript. I used props, emitted events and slots so shared components could support multiple views without being copied.

I first worked with Python at university and wrote my entire engineering thesis in it. I have less commercial experience in Python than in PHP, but I have used it both in my own projects and production systems, including video, audio and image processing.

Commercially I wrote scripts for transforming and analysing large data sets: grouping, filtering and bulk modification of file names, file contents and database records using complex patterns. I also designed IRT-based candidate verification algorithms.

Python was also the basis of my Raspberry Pi property-security system, including remotely connected intercoms using WebSockets, encrypted connections and JWT authentication.

I first used Flask in 2010. I have used it to build REST APIs organised into blueprints, protected with JWT and documented using OpenAPI. Flask-Migrate handled database migrations.

I used Flask-SocketIO for bidirectional communication with remote devices, including Raspberry Pi intercoms communicating over encrypted connections without requiring each device to have a public IP address.

My Raspberry Pi projects combine electronics and software: IR-assisted cameras, microphones, small audio amplifiers, 3 × 4 matrix keypads and displays for user interaction.

Python controlled the complete system, with GPIO libraries for inputs and outputs and Flask-SocketIO for remote communication. I also connected relays and automation controllers.

I designed housings in 3ds Max and prepared them for 3D printing. These are working prototypes covering software, electronics and the physical enclosure.

I have used Photoshop for more than 20 years. When working on websites I can independently prepare the required assets, cut layouts and extract graphic elements including shadows, layered transitions and transparent or semi-transparent material.

I prepare and optimise images and icons by selecting appropriate sizes and compression and removing unnecessary metadata. I also use AI-assisted tools where they are genuinely useful, for example in selection and retouching.

I first used 3ds Max almost 20 years ago through an interest in games and creating virtual worlds. I worked with object and scene modelling, lighting for photorealistic renders, basic animation and simple particle simulations.

For several years I was the lead 3D artist on the hobby project “Mroczne Tajemnice” for Gothic I, preparing assets from concepts through final meshes and textures.

I no longer use 3ds Max every day, but still apply those skills when designing 3D-printable parts and conceptual visualisations, including housings for Raspberry Pi prototypes.