Dan Kononchuk

Unillence

The project involved modernising a microservices-based architecture for a leading fintech company specialising in reloadable prepaid debit cards and personalised financial solutions. The core objective was to enhance the platform’s scalability and feature development speed, transitioning from legacy systems to a microservices platform.

Responsibilities / Achievements:
🔸Took part in solving legacy architecture challenges;
🔸Actively fix bugs and implement new features following TDD;
🔸Regularly gathering and systemising technical details alongside BAs;
🔸Improving general performance by 30% on specific microservices ;
🔸Designed and developed asynchronous communication with Kafka and gRPC;
🔸Achieved over 70% of test coverage using Jupiter and Citrus;

Project Team Size: ~ 20

Technologies:
Spring Web Flux, Project Reactor, gRPC, Kafka, Java 17, MapStruct, PostgreSQL, Citrus Framework, Mockito, JUnit, Opensearch, Kibana, Gradle.

Chief Technology Officer

As a senior software engineer at Unillence, I performed for different clients as a full-stack engineer.|

Achievements:
🔸Solve architecture solutions: implementation of a new class management system and retention of the existing one;
🔸Made refactoring: decouple huge services, migrate to new API, implement architecture for new API integration;
🔸Migrate to recent tech stack: from spring boot 2.7 to 3.0 version, and JDK 8 to JDK 17;
🔸More than 30% of application services are covered, which is about 600 tests;
🔸Implement new functionality: added new features such as credit system accrual and discount flow;

Responsibilities:
🔸Led the implementation of new features from scratch
🔸Maintaining active communication with the product owner and other teams
🔸Integrating the developed web services with other sub-systems
🔸Fixing any legacy bugs
🔸Writing comprehensive unit and integration tests to ensure high-quality code
🔸Conducting thorough code reviews

Project Team Size: 3 - 8 members

Technologies: 

Java 17, Spring Boot/Security, Hibernate 6, Maven, MapStruct, PostgreSQL, ElasticSearch, AWS, S3, Elastic Beanstalk, Lambda, OpenSearch, JUnit 5, Mockito, Stripe, MindBodym NewRelic,
ASP.NET Core 6, Angular 11, Java 17, Azure DevOps, K8S.

Senior Software Engineer

- Automated microservices deployment to Amazon EKS using Helm charts.  
- Developed a retry mechanism for reverse approval transactions, leveraging Amazon SQS and a dedicated retry service for asynchronous processing.  
- Designed and implemented a hydration feature for approval and reverse approval transactions, enabling controlled data distribution between V1 (non-blocking) and V2 (blocking) services.  
- Created integration tests using WireMock, Citrus Framework, and MicronautTest to ensure system reliability and seamless external service interactions.  
- Improved request validation, enrichment, API specifications, and mappers to enhance service functionality.  
- Resolved request ID regeneration issues in multi-microservice calls and fixed logging inconsistencies.  
- Documented new features with detailed explanations and visual charts to support onboarding and knowledge sharing.  

Technologies: Java, Micronaut, AWS (EKS, SQS), Helm, WireMock, Citrus Framework, MicronautTest

Intellias

Project Description:
The microservice-based application stands at the intersection of national fintech and healthcare services for processing, managing, and merging users’ data.

Responsibilities: 
 ▪ Implementing project from scratch
 ▪ Actively working with AWS (SQS, S3, Cognito, Lambda)
 ▪ Developing new functionality / Writing unit tests
 ▪ Taking part in developing backend architecture
 ▪ Actively working with stakeholders 
 ▪ Code review / PI meetings, Spikes

Project Team Size: ~ 35 members

Tools & Technologies:
Java 15, Spring Boot/Cloud/Security, Aws Cognito, S3, Sqs, Lambda, K8S, Gradle, PostgreSql, Temporal 
IO, OpenCSV, MapStruct, Liquibase, Testcontainers

ULC.City

Responsibilities:

🔹As a founding member and CTO of a digital loyalty program startup, I was responsible for the technical implementation of the backend and team recruitment and other typical tasks of a startup founder and CTO.
🔹Through my experience running a startup, I understand the challenges and complexities of building a successful company from the ground up. I deeply appreciate the importance of hiring the right people for a startup and fostering a positive company culture.
🔹I also understand the value of creating a robust technical foundation and how it can contribute to a startup's long-term success.
🔹Responsible for team recruitment, maintaining team spirit, and resolving conflicts

Achievements:
🔸Expanded the team from one to four developers who wrote 80% of the code under my leadership
🔸Mentored four students who successfully started their careers as software engineers
🔸Recruited 5 of the 8 team members during peak development
🔸Successfully handed over the role of CTO to a mentored developer

I left the startup due to the war in the country and my active volunteering activities. Also, there were disagreements with my co-founder friend, but I remain optimistic about its future success.

If you are a startup funder seeking an experienced CTO with hands-on experience running a startup, I am eager to discuss how I can help your company achieve its goals and share my experience with you.

CTO & CoFounder at StartUp

SoftServe

Internal application for aggregating and visualizing data used by employers of big hospitals. 
Microservice-based enterprise which connects people, assets, and data. Used for aggregating and 
visualizing data used by employers of big hospitals. 

Responsibilities:
▪ Developing new functionality / Writing unit tests / Bug fixing
▪ Estimation & Planning
▪ Improving performance
▪ Code review and Knowledge sharing
▪ Gathering requirements

Project Team Size: ~ 15 members

Tools & Technologies:
Java 11, Spring Boot, Hibernate, Google Cloud Spanner, BigQuery, DB2, PubSub, GKE, Kafka, Gradle, 
JUnit, Mockito, MongoDB, Redis.

Project Description: 
Provides software solutions that help small businesses and consumers design online or download templates for further digital printing. 

Responsibilities:
▪ Developing new functionality / Writing unit tests / Bug fixing / Debugging
▪ Estimation & Planning
▪ Preparing Proof of Concept

Project Team Size: ~ 22 team members

Tools & Technologies:
Java 8, JavaEE, Spring Boot, Spring Data JPA, Hibernate, ReastEasy, JAX-WS, WildFly, Apache POI, 
Kafka, Maven, JUnit, Mockito, MongoDB, Postgre, AWS S3, Elasticsearch, Quartz, Docker, GCP

Project Description: 
An internal web application that has to manage customer requests for purchases of various goods 
each is totalling up to $ 1 million.

Responsibilities:
 ▪ Developing new functionality / Writing unit tests / Bug fixing
▪ Mentoring two junior devs
▪ Managing the development process
▪ Actively involved in communication, negotiating, and collaboration with clients
▪ Requirements gathering and analysis
▪ Implemented and achieved significant performance enhancements

Tools & Technologies:
Java 7, Spring MVC, Hibernate, Spring Data Jpa, Lucene, Apache POI, JS, JSP, CSS, jQuery, Angular 2, 
Angular JS, Maven, Bootstrap, Ajax, Git, Junit, Mockito, Oracle DB

Lead Full Stack Engineer

Working as part of the 20 members team in a B2B software provider that uses predictive analytics techniques to deliver prescriptive intelligence that maximises customer lifetime value.

Experience:
‣ Developing new functionality / Writing unit tests / Bug fixing
‣ Preparing a POC together with Tech-lead

Technologies:
Java 5, Java Reflection API, Spring 1.3, Spring MVC, Hibernate, Maven, SVN, Oracle DB

Java Software Engineer

Upwork

Summary: 
As a freelance web developer on Upwork from 2014 to 2016, I developed and maintained web applications for clients across various industries. My expertise is in WordPress development using PHP and JQuery, but I also worked with other technologies such as HTML, CSS, and JavaScript. I am skilled in collaborating with clients to understand their needs and delivering custom solutions that meet their requirements.

Experience:
 •  Collaborated with clients to understand their needs and requirements
 •  Developed custom WordPress themes and plugins using PHP and JQuery
 •  Created responsive and mobile-friendly designs using HTML, CSS, and JavaScript
Debugged and troubleshot issues as they arose
 •  Provided ongoing support and maintenance for websites after they launched
 •  Managed projects to ensure they were delivered on time and within budget
 •  Marketed services and built a brand on Upwork to attract new clients

Achievements:
 ‣  Completed projects on time and within budget, resulting in positive feedback from clients
 ‣  Developed a custom WordPress theme that increased website traffic by 25% for a client in the e-commerce industry
 ‣  Led a team of developers to complete a project 2 weeks ahead of schedule and under budget for a client in the healthcare industry

Overall, my freelance experience on Upwork allowed me to develop diverse skills, including project management, communication, and marketing, in addition to my technical skills in WordPress development using PHP and JQuery.

 Freelance Web Developer | WordPress, PHP, and JQuery Expert

CTO @Unillence | Co-founder @FacingAI | Bringing New Tech for Innovative Solutions

I have actively worked with AWS (SQS, S3, Cognito, Lambda), Spring Boot/Cloud/Security, Azure DevOps, K8S, and many more technologies. I have experience estimating and planning, improving performance, code review, and knowledge sharing. Additionally, I have a strong background in Java.

As a founding partner at an AI/ML startup focused on bringing innovative solutions, I understand the challenges and complexities of building a successful company from the ground up.

As a Chief Technology Officer at Unillence, I am dedicated to driving business profitability through innovative technical solutions. I have a proven track record of leading software development teams and providing strategic guidance for growth, resulting in exceptional results and maximizing ROI for businesses. 


🔹Experienced and passionate CTO who drives business profitability through innovative technical solutions
🔹Leads software development teams and provides strategic guidance for growth
🔹Committed to delivering exceptional results and maximizing ROI for businesses
🔹Let's discuss how I can help your business succeed

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