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Jan – React, Node.js, Typescript, experts in Lemon.io

Jan

From Poland (GMT+2)

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Full-stack Web DeveloperSenior
Hire developer
7 years of commercial experience
Blockchain
Data analytics
E-commerce
Healthcare
NFT
Project management
Public services
Mobile apps
Platforms
Lemon.io stats
2
projects done
1074
hours worked
Open
to new offers

Jan – React, Node.js, Typescript

Jan is a Senior Full-Stack JavaScript Developer with 6+ years of commercial experience, including working for the largest European e-commerce website and developing apps for Fortune Global 500 companies like Netflix, Tesla, Apple, and Uber. Jan wants to share his knowledge and experience with startups and help them rise. Don't miss the opportunity to bring his talent to your team!

Main technologies
React
4 years
Node.js
5 years
Typescript
5 years
JavaScript
5 years
Next.js
3 years
AWS
2 years
React Native
1 year
Additional skills
Angular
Java
Express.js
Webpack
Python
Vanilla JS
Docker
Firebase
Kubernetes
WebSocket
WebRTC
MongoDB
SQL
Redis
ElasticSearch
Bootstrap
Handlebars
Lambda
Ionic
PostgreSQL
GCP
CI/CD
Xcode
Android Studio
DynamoDB
GraphQL
Ready to start
ASAP
Direct hire
Potentially possible

Experience Highlights

Frontend Development Team Lead (at the beginning), Backend Developer
Jan 2022 - Jul 20225 months
Project Overview

This is a mobile APP that allows users to easily follow, manage, and analyze users' favorite NFT collections - for free. The main features he was working on were:

  • A new version of application landing page(React.js, Nest.js)
  • Supporting push notifications on the backend - sending daily push notifications about price changes, making it possible to subscribe/unsubscribe notifications, integration with One Signal _Setup AWS backend infrastructure over Terraform(Database, API Gateway, SNS, MongoDB Atlas Search indexes) _Creating Lambda microservices that can fetch and persisting data about NFTs
Skeleton
Skeleton
Skeleton
Responsibilities:
  • created front-end and back-end architecture;
  • reimplement the existing front-end;
  • debugged and resolved the application issues;
  • wrote unit, integration, and e2e tests;
  • integrated with different providers;
  • increased the performance of the app.
Project Tech stack:
Node.js
React
React Native
PostgreSQL
AWS
Lambda
REST API
Docker
MongoDB
NoSQL
Unit testing
MobX
JavaScript
Next.js
Redis
Lead Developer
Dec 2020 - Nov 202111 months
Project Overview

A medical facility that provides online telemedicine services, focusing on contraception and the treatment of impotence. The team consists of qualified Polish doctors who work in clinics and hospitals in and around Warsaw. The work of doctors is based on a medical interview based on an intelligent e-consultation form. Contact with the doctor is anonymous and safe - the patient does not have to make an appointment for a specific date and time of the visit - he can send an e-consultation request at any time. After its verification by the doctor, the patient receives a four-digit e-prescription code with which he can buy the drug at any pharmacy in Poland.

Skeleton
Skeleton
Skeleton
Responsibilities:

• created a microservice frontend application layer based on business requirements; • cooperated with backend programmers and UX / UI designers; • maintained existing user interfaces and created new functionalities; • designed a clear and sustained application architecture on all levels of abstraction; • performed code decomposition on reusable libraries (Angular, TypeScript, JavaScript); • integrated frontend solutions with the backend platform through the REST API; • shared knowledge, conducted code review; • wrote a good code according to the “clean code” rules; • wrote unit and integration tests.

Project Tech stack:
Typescript
JavaScript (ECMAScript6)
Angular
RxJS
HTML
CSS
CSS
SASS
Webpack
Jasmine
Jest
Protractor
Firebase
Firestore
Firebase Functions
React
WebRTC
Senior Frontend Developer
Jun 2020 - Jun 20211 year
Project Overview

Development of government Portal that provides public data to citizens following the WCAG 2.1 standard. This is a one-stop-shop for data from over 100 public institutions. The website is a source of reliable, constantly updated data, made available free of charge for re-use. An up-to-date list of data providers is available in the Suppliers section.

They have created this website for:

  • citizens interested in the activities of the state;
  • companies that build innovative products and services based on data;
  • NGOs using data in their daily work;
  • scientists carrying out research;
  • officials preparing reports and analyses.
Skeleton
Skeleton
Skeleton
Responsibilities:

Achievements: • Despite the fact that Jan was the youngest developer on the project, backend developers advised with Jan when they needed help in frontend technologies; • Because of tempo of his work, tasks were reassigned to me from other developers in order to be finished in time; • Jan was able to solve issues that were waiting in the project backlog as former team members were unable to close it.

​ Responsibilities: • created a microservice frontend application layer based on business requirements; • cooperated with backend programmers and UX / UI designers; • maintained existing user interfaces and created new functionalities; • designed a clear and sustained application architecture on all levels of abstraction; • performed code decomposition on reusable libraries (Angular, TypeScript, JavaScript); • integrated frontend solutions with the backend platform through the REST API; • shared knowledge, conducted code review; • wrote a good code according to the “clean code” rules; • wrote unit and integration tests.

Project Tech stack:
Typescript
JavaScript (ECMAScript6)
Angular
RxJS
HTML
CSS
CSS
SASS
Webpack
Jasmine
Jest
Protractor
Docker
Ansible
Unleash
Python
Nginx
Frontend Developer
May 2019 - May 20201 year
Project Overview

This is one of the leading project management tools used by over 30 000 teams from companies worldwide. Products are used by CEOs, Managers, Directors, and Project Managers of companies such as Netflix, NASA, Tesla, Apple, Uber, Samsung, Porsche, Siemens, Intel, Boeing, LG, and many more.

Skeleton
Skeleton
Skeleton
Responsibilities:

​ • created a microservice frontend application layer based on business requirements; • cooperated with backend programmers and UX / UI designers; • maintained existing user interfaces and created new functionalities; • designed a clear and sustained application architecture on all levels of abstraction; • performed code decomposition on reusable libraries (Angular, TypeScript, JavaScript); • integrated frontend solutions with the backend platform through the REST API; • shared knowledge, conducted code review; • wrote a good code according to the “clean code” rules; • wrote unit and integration tests.

Project Tech stack:
Typescript
JavaScript (ECMAScript6)
Angular
Redux
NgRx
RxJS
HTML
CSS
CSS
SASS
jQuery
Webpack
Jasmine
Karma
Selenium
Atlassian SDK
Java
Spring
Docker
Senior Frontend Developer
Apr 2021 - Unfinished3 years 2 months
Project Overview

This is the most popular shopping platform in Poland and one of the largest e-commerce websites in Europe (10th most visited e-commerce worldwide). 20 million users per month use it. 1500+ microservices, 60k rps.

Skeleton
Skeleton
Skeleton
Responsibilities:

• ​created a microservice frontend application layer based on business requirements; • cooperated with backend programmers and UX / UI designers; • maintained existing user interfaces and created new functionalities; • designed a clear and sustained application architecture on all levels of abstraction; • performed code decomposition on reusable libraries (Angular, TypeScript, JavaScript); • integrated frontend solutions with the backend platform through the REST API; • shared knowledge, conducted code review; • wrote a good code according to the “clean code” rules; • wrote unit and integration tests.

Project Tech stack:
Typescript
JavaScript (ECMAScript6)
React
Angular
Vue.js
Vanilla JS
RxJS
HTML
CSS
CSS
SASS
Webpack
Jasmine
Jest
Python
Java
Kotlin

Education

2004
Political Science
Bachelor's

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