Kacper Grzeszczyk, Developer in Gdynia, Poland
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Kacper Grzeszczyk

Verified Expert  in Engineering

Software Developer

Gdynia, Poland
Toptal Member Since
June 17, 2022

Kacper is a front-end mobile developer focusing on React and React Native technologies. He leverages them to create cross-platform applications. Furthermore, he is also a programming mentor and has participated in four different programming schools, has been part of over 100 different applications, cofounded Tricity's ReactUp meetup, and mentored more than 100 developers.


Animal Helper
React, React Native, Firebase, Node.js
React, React Native, Node.js
infoShare Academy
React, Cypress, Redux, React Native, User Experience (UX), Agile, Scrum, Kanban




Preferred Environment

React Native, React, Node.js

The most amazing...

...app I've built is the Inscape Meditation App. It had tons of satisfying animations and features, including the Apple Watch integration featured by Apple.

Work Experience

Software Developer Technical Lead

2021 - 2022
Animal Helper
  • Created an application designed to help animals in difficult situations. This application is intended to serve as an emergency number when animals are hurt. The application is a pro bono project.
  • Managed and introduced new developers to projects.
  • Chose the technology stack and helper with the implementation of new functionalities.
Technologies: React, React Native, Firebase, Node.js

Head of Delivery Center

2020 - 2022
  • Managed the software delivery team in the company's Tri-City branch.
  • Led a group of 20 people. Helped them resolve many technical and personal issues.
  • Scaled the organization and managed to go from 4 to 22 people onboard.
  • Performed code audits, code reviews, project estimations, and people evaluations.
  • Made React, React Native, and Node.js applications in multiple industries, including finance, education, and eCommerce.
Technologies: React, React Native, Node.js

Course Instructor

2019 - 2021
infoShare Academy
  • Created the developer's comprehensive front-end course. Prepared and conducted lectures.
  • Watched over the development of the sixteen-person groups. Introduced students to Scrum techniques. Took the role of PO for four groups of four.
  • Wrote tasks on Jira. As a course supporter, helped solve the obstacles in the code encountered by the students.
  • Checked homework assignments, prepared exams, and checked their knowledge.
  • Helped students prepare for the first recruitment interviews.
  • Organized training for external companies to improve their technical knowledge.
Technologies: React, Cypress, Redux, React Native, User Experience (UX), Agile, Scrum, Kanban

Senior Full-stack Developer

2016 - 2020
  • Created applications in React, React Native, and Node.js.
  • Managed React Native specialization. Introduced React Native technology to the company and taught native developers.
  • Recruited new programmers for the company. Co-organized the React'Up conference handled in the Tri-City.
Technologies: React, React Native, Node.js

Course Instructor

2018 - 2019
  • Organized a React course and mentored groups in many cities around Poland. Gave lectures, prepared exercises, and also checked students' homework.
  • Helped to create materials like coding exercises, homework, and decks with slides.
  • Helped students get their first job within a couple of weeks after finishing the course.
Technologies: React, Redux, HTML, CSS, JavaScript

Course Instructor

2016 - 2017
  • Took care of mentoring front-end and full-stack developers.
  • Wrote an entire full-stack course material that consisted of more than 1,000 pages of code explanations. Prepared exercises and projects on Git repositories.
  • Had one-on-one meetings with students where he had a chance to discuss their code issues. Gave them feedback on what to improve and what's good.
Technologies: React, React Native, Node.js, Express.js, MongoDB, HTML, CSS, JavaScript

Angular Developer

2015 - 2017
  • Created specialized business applications using Angular. Designed and created new components using HTML and CSS.
  • Took care of and mentored new people coming to the team.
  • Implemented many complex SaaS applications written in Angular.
Technologies: AngularJS, JavaScript

Inscape Meditation Application

This is an iOS and Android application for meditation. I created the application on both platforms.

Carried out a Watch operating system app implementation mentioned on Apple's App Store. The app had tons of animations and was used by thousands of people worldwide.


A React Native application to find cheap and safe transport of huge packages. I was part of a React Native team and added new app features like searching, filtering, map search, routes, and Push notifications.

Jay Shetty Genius

This is a React Native project working on iOS and Android. It's a well-being Jay Shetty's app. This app is full of video content with two working modes, streaming and offline.

Its purpose is also to be a community hub to share thoughts and notes between the students.


Moodroad is a fashion shopping platform inspired by human moods.

We were asked to create a complex concept for the platform, including naming, visual identity, communication strategy, and the digital experience.

I created UI for the shop and admin panel and connected it to the API.


This is a React Native application to set up and control an intelligent house.

This was a very complex, low-level project that involved a lot of local network setup and working with real-world devices.

Magda Butrym Shop

An official luxury clothing designer ready-to-wear brand store Magda Butrym.

Online fashion store, luxury designer clothes, luxury fashion., and official fashion store. I was part of a React developers team, implemented shop website views according to designs, and connected them to the Shopify API.


JavaScript, TypeScript, GraphQL, HTML, CSS, Swift, Java, Objective-C


React Native, Redux, Express.js, Next.js, Cypress, AngularJS


React, Node.js




Agile, Scrum, Kanban






Remix.run, User Experience (UX)

2012 - 2015

Engineer's Degree in Automation, Robotics, and Control Systems

Gdańsk University of Technology - Gdańsk, Poland