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Jan – Java, React, Spring, experts in Lemon.io

Jan

From Czech Republic (GMT+2)

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Full-stack Web DeveloperSenior
Front-end Web DeveloperSenior
Back-end Web DeveloperSenior
Hire developer
21 years of commercial experience
E-commerce
Healthcare
Logistics
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Jan – Java, React, Spring

Jan is a Senior Full-stack professional with extensive experience in Java, React, and additionally, Kotlin. His expertise spans diverse domains such as logistics, healthcare, and e-commerce. With 6 years of leadership experience, he has progressed from a developer to a manager and eventually to a director, managing teams across Europe and the US. With Jan's extensive expertise and leadership experience, he will definitely bring immense value to any company.

Main technologies
Java
10 years
React
5 years
Spring
10 years
Additional skills
Kotlin
SQL
Java Reactive
Spring Boot
Spring WebFlux
Apollo GraphQL
Redux
Microsoft SQL Server
JUnit
Protractor
RxJS
Ready to start
Flexible / TBD. July, August, or September.
Direct hire
Potentially possible

Experience Highlights

Senior Software Engineer (Back-End)
Sep 2022 - Jan 20241 year 4 months
Project Overview

The project involved developing a new microservice-based e-commerce platform for online shops, replacing the legacy system. The platform was initially deployed in Czechia, followed by Austria, with plans for further rollouts across Europe.

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Responsibilities:
  • Engaged in architectural decision-making processes;
  • Led a code quality and maintainability initiative and was a key member of a task force tackling urgent performance issues before our successful launch in Austria;
  • Developed and introduced a "Deploy Buddy" tool, offering a tailored, one-click overview to facilitate safe and reliable deployments across various services and environments;
  • Developed new features and tests and fixed bugs;
  • Operated in a fully remote environment, with occasional travel to Vienna for collaborative purposes.
Project Tech stack:
Java
Kotlin
Java Reactive
Spring Boot
Spring WebFlux
Senior Software Engineer (Full-Stack)
Mar 2021 - Jul 20221 year 4 months
Project Overview

The project at DHL IT Services involved developing and maintaining two internal applications: a Java Spring Boot user management application used across various DHL applications, which included implementing new features and fixing bugs, and a predictive analytics software for warehouse operations.

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Responsibilities:
  • Initiated the rewrite process from pure JavaScript to TypeScript;
  • Executed the complete rewrite, resulting in significant improvements in code maintainability and readability.
Project Tech stack:
Java
React
Apollo GraphQL
Redux
Spring Boot
Senior Software Engineer (Full-Stack)
Dec 2019 - Feb 20211 year 2 months
Project Overview

The project involved enhancing a Java Spring Boot application for the Collaboration Hub project at a major pharmaceutical company. Its primary focus was on developing new features and resolving bugs. This project played a crucial role in aggregating and presenting "value evidence" documents, supporting value-based healthcare.

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Responsibilities:
  • Developed new features and resolved bugs;
  • Presented new features to stakeholders.
Project Tech stack:
Java
React
Redux
Spring Boot
Performance Engineer Team Lead, Deputy GM, Director of Performance Engineering
Jun 2011 - Sep 20198 years 3 months
Project Overview

A healthcare management application designed to foster managed care techniques that ultimately reduce healthcare costs while maintaining the quality of care.

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Responsibilities:
  • Led performance analysis and optimization, mostly focusing on SQL Server internals and Java;
  • Achieved successive promotions from a Performance Engineer Team Lead to the esteemed role of Deputy General Manager;
  • Managed teams across Prague and Boston, overseeing performance and scalability;
  • Initiated and directed the development of an automated performance testing pipeline for REST web services;
  • Integrated performance engineering workflow with the company-wide Scrum process;
  • Achieved significant performance enhancements, including an 85% increase in supported concurrent users, and maintained 100% SLA compliance for screen response times;
  • Optimized release testing report processes, increasing efficiency;
  • Directed engineering teams and led recruitment efforts;
  • Resolved critical production issues and addressed long-term performance challenges;
  • Mentored team members, guiding their professional growth.
Project Tech stack:
Java
Spring
Microsoft SQL Server

Education

2010
Economics and Management
MSc
2008
Programming, Computer Science
BSc

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