Piotr Biernat

Senior Backend Developer

+48 690-687-724
Gliwice, Poland

About Me

Backend Developer with over 10 years of experience, utilizing advanced object-oriented programming techniques such as design patterns, SOLID, DRY, KISS, YAGNI. Specializing in PHP and Golang. After hours, enthusiast of a good book and film.

Experience

Lead Backend Developer @ Freelancing

2023 — Present
  • Improvement and optimization of DHL courier integration for e-commerce client.
  • Integration of Przelewy24, PayU, and Stripe payment systems for e-commerce client.
  • Expansion of existing modules in e-commerce system - still.shop.

Senior Backend Developer @ ENP

06/2023 — 08/2023
  • Development of proprietary e-commerce platform built in PHP using PostgreSQL and Redis databases with RabbitMQ queue system. Application based on microservices architecture.
  • Planning and creating unit and integration tests.
  • Database maintenance and SQL query optimization.

Senior Backend Developer @ Multiway sp. z o.o.

07/2021 — 11/2022
  • Development of MPK ticketing application in PHP using microservice architecture and PostgreSQL database.
  • Creation and development of advanced SQL migrator for microservice applications.
  • Development and maintenance of above systems using TDD methodology.
  • Database maintenance and SQL query optimization - Redis Cache.

Senior Backend Developer @ iPresso sp. z o.o.

01/2021 — 06/2021
  • Development and maintenance of proprietary application for marketing automation - iPresso.
  • Expansion and testing of RabbitMQ workers.
  • Development and maintenance of iPresso application using TDD approach.
  • Database maintenance and SQL query optimization - Redis Cache.

Application Developer @ Jazzy Innovations sp. z o.o.

02/2019 — 08/2020
  • Development and maintenance of air quality monitoring application — Syngeos.
  • Development and maintenance of tools supporting web application for card game — Magic: The Gathering, based on technologies such as AWS Lambda and NodeJS.
  • Implementation of TDD methodology (unit, integration, and functional tests).

PHP Web Developer @ Testimo sp. z o.o.

04/2018 — 01/2019
  • Development and maintenance of websites based on WordPress.
  • Database maintenance and SQL query optimization.
  • Creation of Cache system based on .htaccess and PHP scripts.

PHP Web Developer @ Positive-Power sp. z o.o.

06/2017 — 02/2018
  • Development and maintenance of websites based on proprietary framework.
  • Creation of REST API endpoints for AJAX requests.
  • Database maintenance and SQL query optimization.

Mid Backend Developer @ Wasko S.A.

09/2016 — 05/2017
  • Development and maintenance of vehicle and train fleet monitoring application.
  • Analysis and improvement of overlapping start and end time readings of vehicles in database.

Mid Backend Developer @ 3a.pl sp. z o.o.

04/2015 — 07/2016
  • Development and maintenance of vehicle and train fleet monitoring application.
  • Creation of dedicated tool for searching colliding start and end time records of vehicles.
  • Creation of module for drawing work zones of vehicles on Google Maps.

Junior Backend Developer @ iSystems sp. z o.o.

02/2011 — 09/2014
  • Development and maintenance of proprietary e-commerce application.
  • Refactoring of base modules and company framework.
  • Independent management of online store implementation in cooperation with client.
  • Creation of advanced product importer with language versions and dynamic attribute value assignment.

Skills

Programming Languages

PHP SQL JavaScript (ES6+) TypeScript NodeJS Golang

Frontend

HTML5 CSS3 React Next.js

Backend

MySQL PostgreSQL MongoDB Redis RabbitMQ

Cloud & DevOps

Docker Kubernetes Microservices Traefik

Featured Projects

Advanced Product Importer for E-commerce System

Data importer from Excel file containing references to dynamically loaded handlers in headers — determining the final data storage location, e.g., product category, quantity of items in stock, etc. To optimize the data reading process and speed up the import — the Excel file was converted to a much simpler NLJSON format, reducing import time by over 50%.

PHP MySQL Cache

Advanced SQL Migrator for Microservices-Based Applications

SQL importer with over 30 custom tokens in the form of: {{datetime|"Europe/Warsaw"}}, {{file-contents|"/path/to/file.txt"}}, etc. — providing unlimited SQL file modification capabilities. Additionally, the importer had two operation modes — scenario mode with a file defining the order of loading specific SQL files, and automatic mode loading files by prefix: 0001-*, 0002-*, etc. Besides SQL files, the importer could execute migrations in the form of PHP files — providing unlimited SQL query capabilities. The entire application was compiled to a single PHAR file.

PHP PostgreSQL Microservices PHAR

Zone Module for Vehicle and Train Fleet Monitoring Application

End user had the ability to define custom zones on Google Maps, after crossing which by a vehicle, an alert was generated in the application.

PHP JavaScript Google Maps

Extension of Traefik Tool with Ability to Load Plugins from Any Repository

Traefik by default handles two types of plugins — downloaded from its own Marketplace, and loaded from local filesystem. My extension allows downloading custom plugins from any repository.

Golang