Ruskin is available for hire

Ruskin Janowski

Verified Expert in Engineering

Back-end Developer

Cape Town, South Africa

Toptal member since October 14, 2022

Expertise

Mathematics Back-end Developers Java SQL Windows Development JUnit REST API Git JSON Spring Boot Jenkins Swagger GIS PostgreSQL GitHub

Bio

Ruskin is a Java developer who believes in writing clean, easy-to-read, and maintainable code that delivers intuitive and practical functionality. He excels in communication, building trust with clients, and providing quality work that meets specifications and is on time. Ruskin is experienced in Spring Boot, PostgreSQL, SQL Server, Docker, Kubernetes, Kafka, Rest APIs, and microservices.

Portfolio

Acrolinx

Java, Spring Boot, PostgreSQL, OpenAI, OpenAPI, Kubernetes, GitLab...

EasyEquities

Java, Spring Boot, Apache Maven, GitHub, Apache Kafka, REST, Swagger...

Peralex

Java, PostgreSQL, GitLab, Jenkins, Gradle, REST, WebSockets, Swing, JUnit...

Experience

Java - 7 years
Spring Boot - 3 years
REST - 3 years
PostgreSQL - 2 years
Apache Maven - 2 years
Redis - 1 year
Apache Kafka - 1 year
Microservices - 1 year

Availability

Part-time

Preferred Environment

Spring Boot, Java, Microservices

The most amazing...

...project I've worked on is an application to visualize spectrum data, resulting in additional funding and team formation.

Work Experience

Senior Java Software Engineer

2023 - PRESENT

Acrolinx

Developed a Java back-end microservice to interface with OpenAI. This service was used as the back end for AI functionality added to the product.
Migrated a Spring Boot microservice from single tenant to multi-tenant. This involved database work, code changes, and understanding the surrounding infrastructure changes.
Helped maintain Java back-end services, including bug fixes and adding new features.

Technologies: Java, Spring Boot, PostgreSQL, OpenAI, OpenAPI, Kubernetes, GitLab, Apache Maven, Gradle, ChatGPT, Argo CD, Docker, Swagger, Java Servlets, JUnit, SQL, CI/CD Pipelines, Artificial Intelligence (AI), Large Language Models (LLMs), AI Chatbots

Java Developer

2022 - 2022

EasyEquities

Developed a microservice that provides pricing data through REST API and Kafka topic to other microservices.
Operated in the Agile process by implementing and demoing features, acting on feedback, and fixing bugs.
Helped maintain production and UAT environments by investigating and identifying issues.

Technologies: Java, Spring Boot, Apache Maven, GitHub, Apache Kafka, REST, Swagger, SQL Server 2014, Redis, Docker, Kubernetes, Microservices, JUnit, Java 11, MongoDB, Spring, Java 8, APIs, Amazon Web Services (AWS), Windows, Stock Market, Stock Trading, REST APIs, API Integration, MySQL, Git, Hibernate, JSON, SQL, Unit Testing, Relational Databases, VM, Microsoft SQL Server, Back-end, Apache Avro, OpenAPI, Java Servlets, CI/CD Pipelines

Java Developer

2019 - 2022

Peralex

Developed a desktop application that recorded, stored, and displayed on a 3D globe various sensor data, such as the movement of ships, cameras, and radar.
Implemented and demoed features, acted on feedback, and fixed bugs, working within the Agile process.
Suggested and implemented UX and architectural code changes for an application to view spectrum data recordings, resulting in the application being used as the basis for a new product and receiving additional funding.

Technologies: Java, PostgreSQL, GitLab, Jenkins, Gradle, REST, WebSockets, Swing, JUnit, Java 11, GIS, OpenStreetMap, Java 8, APIs, Windows, REST APIs, API Integration, Git, JSON, SQL, Unit Testing, Relational Databases, Linux, VM, Back-end

Java Developer

2018 - 2019

Self-employed

Developed an automated trading application for Bitcoin arbitrage that would trade when the arbitrage difference was favorable.
Investigated several different trading strategies, such as spread trading.
Supervised the running of the automated trading application and tracked the trades to ensure they were profitable.

Technologies: Java, WebSockets, REST, Apache Maven, Eclipse, Java 8, APIs, Windows, Microservices, Stock Trading, Automation, Stock Market, REST APIs, API Integration, Git, JSON, SQL, Unit Testing, VM, Back-end

Java Developer

2017 - 2018

Peralex

Developed an application to run automated acceptance test procedures on electronic hardware and implemented existing tests that were previously run via a manual process.
Engaged in the Agile process by implementing features and fixing bugs.
Performed in a team using the Agile methodology to develop, test, and maintain several different desktop applications.

Technologies: Java, Eclipse, Swing, Ant Design, Wix Installer, NetBeans, H2DB, GIS, Java 8, APIs, Windows, Automation, REST APIs, SQL, Unit Testing, Relational Databases, Linux, VM, Back-end

Experience

Low-cost Trading Platform

https://www.easyequities.co.za/

This project was an app for purchasing stocks. I was part of the back-end team and worked on several back-end microservices, which provided prices, processed orders, and updated account balances. The main focus was on high-volume processing, scalability, and moving from a monolith-type back-end application to a microservice-based back end.

Sensor Management System

A desktop application for recording, storing, and visualizing sensor data. This project was an R&D, and I led everything from feature implementation and bug fixing to the choice of used technologies. The application was last in the stage of being proposed as a solution for part of a larger project.

Spectral Graphing Application

An application to visualize and graph spectral data. I was the front-end developer for 3D graphing of data, graphing controls and layout, and some data processing. Additionally, I suggested changes to the UX design and application architecture to revamp the application. The changes were successful, resulting in additional funding for development and the application being used as the basis for a new product.

Education

2012 - 2016

Bachelor's Degree in Electrical Engineering

The University of Cape Town - Cape Town, South Africa

Certifications

MAY 2022 - PRESENT

AWS Certified Cloud Practitioner

Amazon Web Services

Skills

Libraries/APIs

JOOQ, REST APIs, OpenAPI, Java Servlets, FlatBuffers, OpenGL

Tools

IntelliJ IDEA, Jenkins, Gradle, Apache Maven, GitHub, Postman, GIS, Git, GitLab, Kafka Streams, ActiveMQ, Apache Avro, Slack, MATLAB, Jira, Wix Installer, ChatGPT

Languages

Java, Java 11, Java 8, SQL

Frameworks

Spring Boot, Swing, Swagger, JUnit, Spring, Hibernate, Ant Design

Paradigms

REST, Microservices, Automation, Unit Testing

Platforms

Windows, Apache Kafka, Eclipse, NetBeans, Docker, Kubernetes, Amazon Web Services (AWS), Linux

Storage

PostgreSQL, SQL Server 2014, Redis, SQL Server 2016, JSON, Relational Databases, Microsoft SQL Server, MySQL, MongoDB

Other

Mathematics, WebSockets, TCP/IP, H2DB, APIs, Stock Trading, Stock Market, API Integration, Integration Testing, Back-end, CI/CD Pipelines, Physics, OpenStreetMap, VM, OpenAI, Artificial Intelligence (AI), Large Language Models (LLMs), AI Chatbots, Argo CD

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