Oleksandr Lazariev

A large project for a major world grocery retailer. I was a part of a big team of 150+ people—with dedicated developer, QA, automation QA, DevOps, DBA, Android, and iOS teams—to build and support a B2C eCommerce application.

The center of the project was an SAP Hybris application that was integrated with multiple delivery, payment, marketing, and loyalty services in several European countries.

As a member of a development team, I was responsible for integrating the application with various payment providers such as Adyen, Payten, and others, successfully making the logic both abstract and generic when possible, as well as providing the ability to customize it for specific providers.

Another big chunk of responsibilities of our team was to work with Apache Kafka services for both sending and receiving events required for marketing, analytics, and other purposes.

The technology stack for this work included: SAP Hybris platform, Spring Web, MySQL, Apache Ant, ActiveMQ, Apache Kafka, and React.

This was a project for a major hardware manufacturer to build an internal web portal and desktop app responsible for parsing hardware set up outputs and generating reports based on them. Input data sources were unique in terms of data format, the information contained, and more, and each case required special handling and customization.

As a small development team leader, I was responsible for requirements analysis, feasibility and effort estimation, tasks delegation, and implementation of new features. The built platform provided tremendous business value to the company, as it saved many person-hours of highly qualified specialists' work who were able to generate set up reports for customers within a few minutes.

The technology stack for this work included: Spring Web, MySQL, H2 on the back end with Spring and Thymeleaf on the front-end serverside rendering with some Vanilla JS.

A small startup project aimed at providing real-time analytics for electric power supply companies about the state of their equipment with predictions about time left until its failure.

I was the only back-end developer on the project and was involved in multiple stages of development:
Porting existing analytics algorithm was written in VisualBasic in an Excel spreadsheet to Apache Spark calculations.
• Providing a REST API for multiple graphs and diagrams shown on the front end based on these calculations.
• Working on performance optimization of the calculations—the calculation time was reduced from five minutes to around 10-15 seconds.
• Debugging and fixing issues of various complexity, including heap dump analysis to find the root cause of memory leaks.

The technology stack for this work included: Spring Web, PostgreSQL for a REST API, and Apache Spark with Scala for calculations.

This project was of one of the Canadian banks and aimed to build a new digital banking service with some unique features from scratch.

As a small team member, I was solely responsible for designing and building a batch processing service for the reconciliation and settlement of banking transactions.

This standalone application was implemented using a Spring Batch framework that ran as Kubernetes cronjob, was integrated with some external applications, and produced and uploaded reports to AWS S3 storage as a result of the execution.

The technology stack for this work included: Spring Batch, PostgreSQL, Docker, and Kubernetes.

A startup that built a SaaS platform aimed to provide businesses with a solution for automation of their internal and external business processes. The idea of the product was to provide a highly flexible and customizable service for customers to create their own endpoints and automation.

I was part of a medium-sized back-end team and owned multiple platform features:
• Adding support for automated code execution.
• Providing an API for dynamic SQL generation and execution.
• Building a reports module that allowed customers to create and generate reports with various data inputs, providing reports in different formats and more.

One of the special characteristics of the project was the fact that there was and architecture decision not to use any ORM, so there was direct interaction with the database using the iBatis framework with full leveraging of PostgreSQL features like stored procedures, JSON-based search, full-text search, and more.

The technology stack for this work included: Spring Web, iBatis, PostgreSQL, JasperReports, Quartz, and ElasticSearch.

The project was a social network app for employees and clients of a major world cosmetics and beauty products manufacturer that allowed them to share ideas and notes about beauty industry products and news, comment and like each other's posts, and more.

We built Android and iOS apps as well as a managing admin portal. I was the only back-end developer responsible for designing data models, the database structure, and providing the API to all clients.

The technology stack for this work included: Jax-RS, Guice, PostgreSQL, ElasticSearch, Hibernate, and AWS.

A solution aimed to provide a personalized recommendation engine to help customers find the beauty product matching their needs and concerns for a small startup in the beauty industry. The platform is a B2B solution-first, allowing beauty e-shops to add a custom widget with recommendations of their products to their shops.

I was the only full-time developer on the project, and my responsibilities included the whole cycle of the application development:
• Requirements gathering and analysis.
• Tasks estimation.
• Feature implementation.
• Code deployment.
• Infrastructure setup.
• Load testing,
and more.

The technology stack for this work included: Scala, Play Framework, BackboneJS, MongoDB, JMeter, and AWS.