Ganna Skirko, Developer in St. Petersburg, FL, United States
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Ganna Skirko

Verified Expert  in Engineering

Back-end Developer

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.


Java, Python, Go, Solidity, Cosmos SDK, Hedera Hashgraph
Java, Python, Amazon Web Services (AWS), Event-driven Architecture
Python, ETL, Amazon Web Services (AWS), Kubernetes, Docker




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 Penetartion Tester

2023 - PRESENT
  • Became a top hacker for Hedera Hashgraph. Found multiple vulnerabilities in Comet BFT and Rootstock.
  • Performed security assessments and penetration testing to pinpoint vulnerabilities in systems and networks. Created multiple exploits to showcase the implications of identified security issues.
  • Specialized in hacking crypto applications via my profile at HackerOne.
Technologies: Java, Python, Go, Solidity, Cosmos SDK, Hedera Hashgraph

Cloud Application Architect

2022 - 2023
  • 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
  • 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
  • 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, API Integration

Lead Software Developer

2020 - 2020
  • 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, API Integration

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, API Integration

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, API Integration

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
  • 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

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
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
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.
2008 - 2012

Bachelor's Degree in Informatics and Applied Mathematics

Oles Honchar Dnipro National University - Dnipro, Ukraine

APRIL 2023 - APRIL 2026

AWS Certified Data Analytics – Specialty

Amazon Web Services


AWS Certified Solutions Architect Associate


AUGUST 2022 - AUGUST 2025

AWS Certified Cloud Practitioner

Amazon Web Services


REST APIs, JPA 2, Selenium Grid, Apache Jackrabbit


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


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


Event-driven Architecture, Microservices, ETL, DevOps


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


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


JSON, MySQL, Redis, Cassandra


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

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