Andrej is available for hire
Hire AndrejAndrej Kaurin
Verified Expert in Engineering
Node.js Developer
Banja Luka, Bosnia and Herzegovina
Toptal member since June 10, 2015
Bio
Andrej is an organized, highly motivated, and detail-oriented problem solver. He has thirteen years of professional experience in web app development using various technologies, covering both the back and front ends. Creating a great user experience through new, innovative ways of user interaction is and will always be his greatest passion.
Portfolio
Socialflo Solutions Inc.
Angular, React, JavaScript, CSS, HTML, NestJS, Jest, UI Components, REST APIs...
Quorus Inc
React, Next.js, TypeScript, Tailwind CSS, Data Visualization, Dashboards...
JSGuru
Angular, NestJS, React, Flutter, PostgreSQL, CSS3, Material UI, HTML5...
Experience
- Node.js - 13 years
- JavaScript - 12 years
- Angular - 7 years
- React - 7 years
- NestJS - 5 years
- TypeScript - 5 years
Preferred Environment
Git, WebStorm, OS X, Jest, Pixel Perfect
The most amazing...
...application I've built is a web-based learning platform used by thousands of people.
Work Experience
Angular and React Front-end Developer
2024 - 2024
Socialflo Solutions Inc.
- Converted an Angular application into a React application using API references and Figma designs.
- Established scalable architecture with state management and responsive UI.
- Created Storybook documentation with a comprehensive component library.
Technologies: Angular, React, JavaScript, CSS, HTML, NestJS, Jest, UI Components, REST APIs, GraphQL, Charts, D3.js, Apollo Server, Mobile-first Design, Responsive Design, Responsive UI, UI Development, Proof of Concept (POC), Claude, Supabase, PrimeNG
Front-end Developer
2023 - 2023
Quorus Inc
- Developed a new front end for the portfolio management dashboard.
- Created a scalable architecture with state management.
- Created Storybook documentation with a comprehensive component library.
Technologies: React, Next.js, TypeScript, Tailwind CSS, Data Visualization, Dashboards, UI Components, REST APIs, React Query, React Router, Tailwind UI, Styled-components, UI Testing, GraphQL, Charts, D3.js, Apollo Server, Mobile-first Design, Responsive Design, Responsive UI, UI Development, Proof of Concept (POC), Claude, Supabase
CTO
2018 - 2022
JSGuru
- Scaled the company team from five to 70+ people of experienced engineers.
- Created a framework of reusable components for common industry challenges in order to create rapid development.
- Created and supported engineering teams to support three startups to scale from 0 to more than 10 million in value.
Technologies: Angular, NestJS, React, Flutter, PostgreSQL, CSS3, Material UI, HTML5, Responsiveness, Tailwind CSS, Next.js, UI Design, Azure Active Directory, B2B, Single-page Applications (SPAs), Figma, Front-end, REST, Full-stack, Architecture, Craft CMS, User Experience (UX), Web Design, Design, Salesforce, React Redux, Front-end Development, UX Design, Search Engine Optimization (SEO), MySQL, WebSockets, Component Libraries, RxJS, Content Management Systems (CMS), UI Components, Amazon Web Services (AWS), Vite, REST APIs, React Query, React Router, Tailwind UI, Node.js, Styled-components, GraphQL, Charts, Apollo Server, Mobile-first Design, Responsive Design, Responsive UI, UI Development, Proof of Concept (POC), Claude, Supabase
Software Engineer
2015 - 2019
CloudAge
- Engineered an invoice-loading process using AWS Lambda, S3, and SQS to support thousands of invoice loads daily.
- Created back-end architecture using Node.js, PostgreSQL, and AWS services to support complex telecom accounting processes.
- Established a CI/CD process to deliver daily deployments.
- Architected and developed a custom UI framework to develop new components and pages rapidly.
Technologies: PostgreSQL, Node.js, React, Storybook, CSS, HTML, CSS3, Pixel Perfect, User Interface (UI), Angular, AngularUI, HTML5, Mobile First, Responsiveness, Tailwind CSS, UI Design, Azure Active Directory, B2B, Single-page Applications (SPAs), Figma, Front-end, REST, Full-stack, Architecture, User Experience (UX), Web Design, Design, Web UI, React Redux, Front-end Development, UX Design, Search Engine Optimization (SEO), MySQL, WebSockets, Component Libraries, RxJS, Data Visualization, Content Management Systems (CMS), Amazon Web Services (AWS), REST APIs, React Query, React Router, Tailwind UI, Styled-components, D3.js, Mobile-first Design, Responsive Design, Responsive UI, UI Development, Proof of Concept (POC), Supabase
Front-end Engineer
2015 - 2016
Mobile Guardian
- Created a responsive dashboard application.
- Developed the core front-end framework.
- Generated an automated build and publish system.
Technologies: Less, JavaScript, Redux, CSS3, Pixel Perfect, User Interface (UI), Angular, HTML5, Responsiveness, Azure Active Directory, B2B, Single-page Applications (SPAs), Figma, Front-end, Architecture, User Experience (UX), Web Design, Design, Web UI, React Redux, Front-end Development, UX Design, Search Engine Optimization (SEO), MySQL, WebSockets, Component Libraries, RxJS, Data Visualization, Content Management Systems (CMS), React Router, Tailwind UI, Responsive UI, UI Development
Full-stack Web Developer
2013 - 2015
FOUNDER.org
- Created a social platform supporting the learning and development process of entrepreneurs.
Technologies: SCSS, Node.js, JavaScript, Responsive, CSS3, Pixel Perfect, User Interface (UI), Angular, HTML5, Responsiveness, Azure Active Directory, Bootstrap, B2B, Single-page Applications (SPAs), Figma, REST, Full-stack, Architecture, Web Design, Design, Web UI, React Redux, Front-end Development, MySQL, WebSockets, Component Libraries, RxJS, Data Visualization, Content Management Systems (CMS), UI Components, React Router, Responsive UI, UI Development
Front-end Developer
2010 - 2013
Procyon Media
- Developed a web-based level learning management platform.
- Created an eCommerce system selling digital goods.
- Created a web-based back-office for outdoor media planning and warehousing.
Technologies: Knockout (Knockout.js), JavaScript, APIs, CSS3, Pixel Perfect, User Interface (UI), Responsiveness, Azure Active Directory, ASP.NET, Bootstrap, B2B, Single-page Applications (SPAs), Figma, Front-end, Web Design, Design, MySQL, WebSockets, Component Libraries, Data Visualization, Content Management Systems (CMS), UI Components, Responsive UI, UI Development
Web Developer
2007 - 2010
Rainfall
- Created a web-based application for transportation logistics.
- Developed a web-based content management system.
Technologies: JavaScript, CSS3, Pixel Perfect, User Interface (UI), Responsiveness, ASP.NET, Bootstrap, Single-page Applications (SPAs), PHP, Design, .NET, UI Development
.NET Web Developer
2006 - 2007
Telerik
- Developed a web content management system.
Technologies: Object-relational Mapping (ORM), JavaScript, CSS3, Pixel Perfect, User Interface (UI), ASP.NET, Bootstrap, Single-page Applications (SPAs), Design, .NET, UI Components
Full Stack Engineer
2002 - 2006
Orange Solutions
- Created a web-based transportation logistics and warehousing system.
- Created a universality system for student and curriculum management.
Technologies: JavaScript, CSS3, User Interface (UI), ASP.NET, .NET
Experience
CloudAge | Telecom Management Software
Cloud Age provides telecom service providers, TEMs, enterprises, and MSPs with cost-effective SaaS solutions to automate telecom data-intensive processes enabling business intelligence for lifecycle cost management—freeing up resources to focus on higher value activities.
Mobile Guardian - School Dashboard
https://www.mobileguardian.com/Mobile Guardian exists to offer mobile devices MDM & protection, empowering parents and schools in managing smartphones and tablets efficiently, simply, and cost effectively.
FOUNDER.org - Social Collaboration Platform
An organization investing in student entrepreneurs solving big problems and helping these courageous innovators to build great companies. My contribution included creating a business model, web API, and front-end framework, and leading the entire front-end team.
SelfNet – eCommerce Platform for Insurance
SelfNet was a project creating a web portal for RSA insurance in the United Kingdom. The software was developed under contract with Bluewrasse, a UK software company. My contribution included development of the web portal instance, creation of the back-end and front-end architecture, and leading the web team.
Qusion - Content Management Framework
Qusion is an advanced content management framework developed for satisfied developers and end-user needs for a web site or portal manipulation and management. My contribution included creation of the core idea, development of the business model, and management of the development team.
LearningCubes - Learning Management System
An advanced enterprise-level learning management system.
Telerik SitFinity – Content Management System
Sitefinity is a development platform for construction and management of websites, community portals, and intranets. Inspired by Web 2.0 UIs, the product delivers a top experience for end users, while the flexible architecture empowers developers to be in full control. My contribution included creation of specifications for various controls, evaluation of ORM tools, and software development.
Transmission - OHR Transport System
I programmed a business layer and user interface using C#/ASP.NET technology, XML, XSL, JavaScript, DHTML-a and CSS-a. The security system development and implementation is based on horizontal and vertical access to application modules and stability control as well. It features GUI standard definition and module cooperation definition.
Web App Connecting Agencies and Creators
I worked on transitioning a concert application from Angular to React. This app aimed to simplify processes for agencies collaborating with creators and influencers. My primary role involved converting the legacy Angular application into a modern React framework.
Education
2015 - 2016
Certified NLP Practitioner in NLP Practitioner
International Association for Neuro-Linguistic Programming - Belgrade, Serbia
1995 - 1999
Technical High School Degree in Computer Science
Nikola Tesla High School - Banja Luka, Bosnia and Herzegovina
Certifications
NOVEMBER 2019 - PRESENT
Rutgers Mini MBA
Rutgers University
Skills
Libraries/APIs
Node.js, jQuery, React, React Redux, REST APIs, Google API, jQuery UI, RxJS, React Query, React Router, D3.js, PrimeNG, AngularUI, Amazon EC2 API
Tools
Jira, GitHub, Git, Figma, Claude, WebStorm, Amazon Simple Queue Service (SQS)
Languages
JavaScript, CSS, TypeScript, HTML, CSS3, HTML5, ECMAScript (ES6), SQL, Sass, Less, GraphQL, SCSS, PHP
Frameworks
Angular, NestJS, Next.js, Bootstrap, Knockout (Knockout.js), Kendo UI, Redux, Jest, Tailwind CSS, ASP.NET, .NET, Flutter, Material UI, Express.js
Paradigms
UI Design, REST, Scrum, Kanban, Responsive, B2B, UX Design, Object-relational Mapping (ORM), Search Engine Optimization (SEO)
Storage
Azure Active Directory, MySQL, PostgreSQL, MongoDB, Amazon DynamoDB
Industry Expertise
Web Design
Platforms
Amazon Web Services (AWS), Craft CMS, OS X, MacOS, Windows, AWS Lambda, Salesforce
Other
APIs, Pixel Perfect, User Interface (UI), Mobile First, Responsiveness, Single-page Applications (SPAs), Front-end, Full-stack, Architecture, User Experience (UX), Design, Front-end Development, WebSockets, Component Libraries, UI Components, Tailwind UI, Mobile-first Design, Responsive Design, Responsive UI, UI Development, Proof of Concept (POC), Supabase, Storybook, Web UI, Data Visualization, Content Management Systems (CMS), Vite, Styled-components, UI Testing, Charts, Apollo Server, Dashboards
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