Ganna is available for hire

Ganna Skirko

Verified Expert in Engineering

Back-end Developer

Location

St. Petersburg, FL, United States

Toptal Member Since

July 20, 2022

Ganna is a certified AWS solutions architect and a seasoned software engineer with over 12 years of professional experience. With deep knowledge across multiple tech stacks and domains, she excels at reverse engineering and solving complex technical challenges. Ganna works fast and believes that most things can be implemented; it's just a question of time.

Algorithms Java SQL REST APIs JSON Java 8 Spring Boot Microservices Hibernate Amazon Web Services (AWS)Programming Web Scraping Oracle Spring Shell

Portfolio

HackerOne

Java, Python, Go

Amazon.com

Java, Python, Amazon Web Services (AWS), Event-driven Architecture

Finicity

Python, ETL, Amazon Web Services (AWS), Kubernetes, Docker

Experience

Java - 12 years Spring - 8 years Shell - 7 years Python - 5 years Google Cloud Platform (GCP) - 4 years Amazon Web Services (AWS) - 4 years Kubernetes - 2 years ETL - 1 year

Availability

Full-time

Preferred Environment

IDEA IDE, PyCharm, WebStorm

The most amazing...

...thing I've developed is a serverless, microservices-based AI tool that collects, processes, and analyzes data and generates predictions.

Work Experience

Freelance Ethical Hacker

2023 - PRESENT

HackerOne

Became a top hacker in hacking a cryptocurrency app.
Worked on ethical hacking engagements on HackerOne.
Specialized in hacking crypto apps via my profile: hackerone.com/unknown_feature.

Technologies: Java, Python, Go

Cloud Application Architect

2022 - 2023

Amazon.com

Designed, supported, and developed native cloud applications.
Migrated an application from on-premise to AWS Cloud, including hybrid use cases.
Supported customers continuously in their journey to the cloud.

Technologies: Java, Python, Amazon Web Services (AWS), Event-driven Architecture

Software Architect

2021 - 2022

Finicity

Built ETL pipelines used for processing huge amounts of data.
Owned several machine learning (ML) based projects that were critical for the company while fixing the project's bugs.
Mentored junior developers and helped them with their tasks.

Technologies: Python, ETL, Amazon Web Services (AWS), Kubernetes, Docker

Senior Software Engineer

2021 - 2021

Backblaze

Integrated the team responsible for the lowest level functionality of the cloud storage: file sharding and upload balancing.
Identified and fixed multiple problems that increased the application's throughput output almost twice.
Implemented a system to verify configurations across servers.
Provided production support for the part of the system my team was in charge of.

Technologies: Java, Cassandra, Ansible, Python

Lead Software Developer

2020 - 2020

Nike

Helped the team with their ongoing tasks as part of my role.
Designed and implemented several significant tasks.
Provided production support and helped other developers succeed.

Technologies: Java, Terraform, Spring, Amazon Web Services (AWS), Microservices

Senior Software Engineer

2019 - 2020

JPMorgan Chase

Worked in the merchant services team that is responsible for all incoming transactions.
Performed many complicated refactoring and migration tasks that successfully went to production.
Troubleshot and fixed complex problems that affected customers' experience and blocked further development processes.
Mentored new developers and read them a few lectures about the technologies.
Organized and led the team in completing a complex project.

Technologies: Java, OSGi, Apache Karaf, Apache Camel, Apache Tomcat, WebLogic, Cryptography, Python, Shell, DevOps, Perl, Oracle, Amazon Web Services (AWS), Event-driven Architecture, Microservices

Senior Software Engineer

2016 - 2018

EPAM Systems USA

Worked as an independent consultant on Epam's customers' sites.
Designed and developed distributed applications that operate under a high load.
Mentored developers and helped them to learn the technologies we were using.
Collaborated closely with the leadership team to plan future development activities.

Technologies: Java, Spring, Spring Boot, Oracle, Amazon Web Services (AWS), Google Cloud Platform (GCP), Docker, IBM MQ, RabbitMQ, Selenium, Selenium Grid, Python, Event-driven Architecture, Microservices

Senior Software Engineer

2014 - 2016

EPAM Systems UA

Worked as a technical lead on multiple eCommerce projects for a large corporation that was a customer of Epam Systems.
Designed and helped to develop multiple AEM and Spring-based projects.
Provided application support for the software we developed.
Interviewed and mentored new team members starting on the projects I was in charge of.

Technologies: Java, Adobe Experience Manager (AEM), OSGi, Apache Sling, Apache Jackrabbit, MySQL, Spring, Java 8, Hibernate, JPA

Staff Software Engineer

2010 - 2014

ISD UA

Led a team of four developers for the last two years working in the company.
Designed, built, and provided support to software used in NA.
Interviewed and mentored developers while helping them stay motivated and productive.
Worked closely with the higher management and architects to plan the scope of the work.

Technologies: Java, JPA 2, Oracle, Hibernate, Java EE, WebLogic, JBoss, Apache Tomcat, Perl, Python, Shell, Documentation, CI/CD Pipelines, Mentorship, Apache Maven, Ant Design, SQL

Experience

Predicted.Me

https://predicted.me/

An AI-based tool that collects, processes, and analyzes data and generates predictions. It's a fully serverless, microservices-based application that uses Python for the back end and Flutter for the front end.

GCP Redis Web Console

https://github.com/unknownfeature/redis_client

A web console for Redis that I set up in GCP. The app is serverless—just a Cloud Function with a Go web template. The request goes from the browser to the Cloud Function, communicating with Redis through the virtual private cloud connector.

Distributed Controller-workers Systems

https://github.com/unknownfeature/dcw/

An app designed as a framework that can run distributed jobs and scale the work horizontally. The controller supplies workers with small batches, and workers verify each item in the batch. If the verification is successful, the worker will return the verified item to the controller.

This initial implementation can only brute force using different types of alphabets and verify through the HTTP request. I plan to add vocabulary and cryptography in the future, but it's designed to be a generic runner. Deployment may be done to managed and unmanaged Kubernetes clusters.

Skills

Languages

Java, SQL, Java 8, Python, Go, Perl, Python 3

Frameworks

Hibernate, JPA, Spring Boot, OSGi, Spring, Selenium, Apache Felix (OSGI), Ant Design, Apache Camel, Flutter

Libraries/APIs

REST APIs, JPA 2, Selenium Grid, Apache Jackrabbit

Paradigms

Event-driven Architecture, Microservices, ETL, DevOps

Platforms

Amazon Web Services (AWS), Oracle, Java EE, Google Cloud Platform (GCP), Docker, Kubernetes, JBoss

Storage

JSON, MySQL, Redis, Cassandra

Other

AWS Certified Solution Architect, Enterprise Architecture, Algorithms, API Integration, Programming, Mentorship, Web Scraping, Mathematics, WebLogic, Documentation, CI/CD Pipelines, Cryptography, Networks, SDKs

Tools

Shell, IBM MQ, RabbitMQ, IDEA IDE, PyCharm, WebStorm, Apache Tomcat, Apache Maven, Apache Sling, Apache Karaf, Terraform, Ansible, Adobe Experience Manager (AEM)

Education

2008 - 2012

Bachelor's Degree in Informatics and Applied Mathematics

Oles Honchar Dnipro National University - Dnipro, Ukraine

Certifications

APRIL 2023 - APRIL 2026

AWS Certified Data Analytics – Specialty

Amazon Web Services

SEPTEMBER 2022 - SEPTEMBER 2025

AWS Certified Solutions Architect Associate

AWS

AUGUST 2022 - AUGUST 2025

AWS Certified Cloud Practitioner

Amazon Web Services

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