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Ivan Spoljaric
Verified Expert in Engineering
Full-stack Software Developer
Zagreb, Croatia
Toptal member since April 22, 2022
Bio
Ivan is a versatile full-stack developer with over six years of experience. He excels in JavaScript and TypeScript, leveraging Node.js, Express.js, and NestJS for back-end development, and React, Angular, and Vue for front-end development. Ivan's expertise spans automotive, edtech, IIoT, logistics, GenAI, and forestry sectors, to name a few. Committed to clean and maintainable code, he consistently delivers efficient, scalable, and innovative software solutions that drive business success.
Portfolio
Shancorps Development, LLC
React, TypeScript, Full-stack, Python, Next.js, Tailwind CSS, MongoDB, Shadcn...
One of The Top 3 Global Consultancies
React, CSS, Tailwind CSS, User Experience (UX), User Interface (UI), Python...
One of The Top 3 Global Consultancies
JavaScript, TypeScript, React, Angular, Vue, Node.js, Express.js, GraphQL...
Experience
- React - 6 years
- Software Development - 6 years
- Web Development - 6 years
- TypeScript - 6 years
- Node.js - 5 years
- Full-stack Development - 4 years
- Express.js - 3 years
- Python 3 - 2 years
Preferred Environment
MacOS, Slack, Visual Studio Code (VS Code), Chrome, Terminal, Windows Subsystem for Linux (WSL)
The most amazing...
...thing I've worked on is an app to securely connect to and control a remote target device from anywhere. It is used by millions of users around the world.
Work Experience
Full-stack React/TypeScript Engineer
2025 - 2025
Shancorps Development, LLC
- Built a "customer first-time/onboarding experience" feature E2E (Python, Next.js).
- Developed business "domain use-case" logic in Python/FastAPI.
- Built UI features in Next.js 14. Utilized agent-driven development with Claude and Cursor.
Technologies: React, TypeScript, Full-stack, Python, Next.js, Tailwind CSS, MongoDB, Shadcn, FastAPI, AWS App Runner, Amazon Web Services (AWS), Architecture, Web Architecture, Zustand, Responsive UI, Web Accessibility, WCAG 2, Communication, SaaS, Responsiveness, Enterprise, RESTFul APIs, Test-driven Development (TDD), Databases, Prisma, PostgreSQL, Supabase, Cursor AI, Figma, UI Testing, AI Tools, Application State Management, Page Speed Optimization, Claude Code, Auth0
Senior Full-stack Developer
2023 - 2025
One of The Top 3 Global Consultancies
- Managed a GenAI writing platform for creating structured documents and automating E2E workflows.
- Developed an intuitive UI in Next.js 14 that enables a user-friendly experience. The core of the UI is a real-time, collaborative WYSIWYG editor where the Writer AI agent can stream LLM-generated content.
- Built collaborative Google Docs style comments using Tiptap and Lexical editors, Yjs as a CRDT sync engine with shared data types to merge conflict-free changes from different users in real time, on top of a WebSocket back end.
- Implemented a full-stack, E2E permissioning system based on a combination of RBAC (role-based) / ABAC (attribute-based) architecture using the Casbin authorization library.
- Set up and implemented various e2e feature tests with Cypress and Cucumber (to support BDD Gherkin syntax).
Technologies: React, CSS, Tailwind CSS, User Experience (UX), User Interface (UI), Python, Next.js, Node.js, Lexical.js, Tiptap.js, Cypress, Zustand, CRDT, WebSockets, Webflow, FastAPI, Amazon Web Services (AWS), Python 3, MySQL, Vite, Web Content Accessibility Guidelines (WCAG), Architecture, Web Architecture, Responsive UI, Web Accessibility, WCAG 2, Communication, SaaS, Responsiveness, Enterprise, RESTFul APIs, Test-driven Development (TDD), Artificial Intelligence (AI), Large Language Models (LLMs), Databases, Prisma, PostgreSQL, Supabase, Cursor AI, Tailwind UI, Figma, UI Testing, AI Tools, Application State Management, Page Speed Optimization, Claude Code, Auth0
Senior Full-stack Developer
2022 - 2023
One of The Top 3 Global Consultancies
- Managed an enterprise web app that enables key stakeholders of a large forest industry group to make strategic decisions.
- Built a highly customized React front end for an analytics product. This involved implementing a lot of complex data visualizations with charts, geo maps, tables, and Sankey diagrams using libraries such as D3.js, Deck.gl, and Chart.js.
- Built a highly interactive and data-driven map visualization with Deck.gl. One of the core features was showing aggregated flows of complex domain "data" between different geographic locations.
- Developed software according to industry best practices, like clean architecture and test-driven development (TDD).
Technologies: JavaScript, TypeScript, React, Angular, Vue, Node.js, Express.js, GraphQL, MongoDB, Sequelize, PostgreSQL, Redux, Git, Jest, Cypress, Mocha, HTML5, CSS3, Styled-components, Web Development, Front-end, Full-stack, Nuxt.js, AmCharts, SCSS, HTML, CSS, Next.js, Education, Responsive Web Apps, React Query, APIs, REST, Back-end, Mongoose, Visual Studio Code (VS Code), Software, Software Development, Web App Development, JSON, JSON Web Tokens (JWT), Webpack, Responsive Web Design (RWD), Mobile First, A11Y, User Interface (UI), Dashboards, Python, FastAPI, Bootstrap, Bootstrap 4, Material UI, Tailwind CSS, CSS-in-JS, TYPO3, Webpack 4, Figma, OAuth, Ionic 4, React Native, Storybook, Azure DevOps, Deck.gl, D3.js, Chart.js, React Redux, React Hooks, Unit Testing, E2E Testing, React Router, JSX, React Apollo, Data Visualization, Front-end Development, Server-side Rendering (SSR), TanStack Table, Windows Subsystem for Linux (WSL), Full-stack Development, NestJS, Back-end Development, Web, Integration Testing, Software Engineering, ESLint, Linux, Jira, JavaScript Testing, Search Engine Optimization (SEO), Docker, Containerization, Design, Drizzle, tRPC, Accessibility, jQuery, Less, SMACSS, Sass, Progressive Web Applications (PWAs), GitHub, Netlify, Three.js, Redux Toolkit, Chrome Extensions, User Experience (UX), Testing, Web Usability, Minimum Viable Product (MVP), Pixel Perfect, OpenAI, Vercel, Front-end Architecture, Microfrontends, Contentful, WYSIWYG Web Builders, Shadcn, UI Components, Design Systems, B2B, UI Development, Webflow, Amazon Web Services (AWS), Python 3, MySQL, Vite, Web Content Accessibility Guidelines (WCAG), Architecture, Web Architecture, Zustand, Responsive UI, Web Accessibility, WCAG 2, Communication, SaaS, Responsiveness, Enterprise, RESTFul APIs, Test-driven Development (TDD), Databases, Prisma, Cursor AI, Tailwind UI, UI Testing, AI Tools, Application State Management, Page Speed Optimization, Claude Code, Auth0
Web Development Tutor
2022 - 2022
CareerFoundry
- Evaluated students' submissions carefully and guided them through each exercise.
- Provided constructive feedback to students within 24 hours.
- Highlighted the students' areas for improvement and where they've made the most significant progress.
Technologies: JavaScript, CSS, HTML, Web Development, Node.js, Express.js, MongoDB, APIs, Tutoring, Education, Responsive Web Apps, Visual Studio Code (VS Code), Software Development, TypeScript, React, Angular, Vue, Redux, Git, HTML5, CSS3, Styled-components, Front-end, Web App Development, REST APIs, Webpack 4, Responsive Web Design (RWD), A11Y, Mobile-first Design, Bootstrap, React Redux, React Hooks, Unit Testing, Windows Subsystem for Linux (WSL), NestJS, Software, Bootstrap 4, Material UI, Front-end Development, Web, Next.js, Software Engineering, ESLint, Jira, JavaScript Testing, Prisma, Drizzle, tRPC, Accessibility, jQuery, Less, SMACSS, GitHub, Netlify, Chrome Extensions, User Experience (UX), Testing, Web Usability, Nuxt.js, Pixel Perfect, Front-end Architecture, UI Components, UI Development, Web Content Accessibility Guidelines (WCAG), Responsive UI, Web Accessibility, WCAG 2, Communication, Responsiveness, Enterprise, Test-driven Development (TDD), UI Testing, Application State Management, Page Speed Optimization
Full-stack Software Developer
2019 - 2022
Comsysto Reply
- Contributed to an enterprise web app to securely connect to and control a remote target device, such as a PC or mobile, from anywhere. The app is used by millions of users worldwide.
- Worked on an enterprise web app that enables car manufacturers to efficiently upgrade and convert base commercial vehicles of a big automobile brand into specific purpose vehicles, such as logistics, medical, transportation, and other sectors.
- Worked on an enterprise web app for real-time condition monitoring and screening industrial machines, such as vibrating feeders.
- Worked on an enterprise web app used as a premium mobility and car rental service.
- Mentored junior colleagues on Agile and Scrum methodologies and software development.
- Held React workshops for university students on college meetup events.
- Participated in the company interviewing process and screening of new candidates.
Technologies: JavaScript, TypeScript, React, Angular, Vue, Node.js, Express.js, GraphQL, MongoDB, Sequelize, PostgreSQL, Redux, Git, Jest, Cypress, Mocha, HTML5, CSS3, Styled-components, Web Development, Front-end, Nuxt.js, AmCharts, SCSS, HTML, CSS, Next.js, Education, Responsive Web Apps, Zustand, React Query, APIs, Tutoring, Back-end, Full-stack, Mongoose, Visual Studio Code (VS Code), Software Development, Web App Development, JSON Web Tokens (JWT), REST APIs, Webpack 4, Responsive Web Design (RWD), A11Y, Mobile-first Design, User Interface (UI), Dashboards, Java, Bootstrap, Tailwind CSS, CSS-in-JS, TYPO3, Webpack, Figma, JSON, OAuth, Ionic 4, React Native, Storybook, React Redux, React Hooks, Unit Testing, E2E Testing, React Router, JSX, React Apollo, Front-end Development, Server-side Rendering (SSR), Windows Subsystem for Linux (WSL), Full-stack Development, NestJS, REST, Software, Bootstrap 4, Material UI, Data Visualization, Back-end Development, Web, Integration Testing, Software Engineering, ESLint, Linux, Jira, JavaScript Testing, Search Engine Optimization (SEO), Docker, Containerization, Design, Python, Prisma, Drizzle, tRPC, Accessibility, jQuery, Less, SMACSS, Sass, Progressive Web Applications (PWAs), GitHub, Netlify, Jekyll, Three.js, Redux Toolkit, Chrome Extensions, User Experience (UX), Testing, Web Usability, Minimum Viable Product (MVP), Pixel Perfect, Front-end Architecture, Microfrontends, Contentful, Content Management Systems (CMS), Headless CMS, Shadcn, UI Components, Design Systems, B2B, Ant Design, UI Development, Amazon Web Services (AWS), MySQL, React Testing Library, Web Content Accessibility Guidelines (WCAG), Architecture, Web Architecture, Responsive UI, Web Accessibility, WCAG 2, Communication, SaaS, Responsiveness, Enterprise, RESTFul APIs, Test-driven Development (TDD), Databases, Supabase, UI Testing, Application State Management, Page Speed Optimization, Auth0
Full-stack Software Developer
2019 - 2019
Speck
- Developed an online education platform that provides after-school STEM and sports enrichment programs and summer camps for kids.
- Taught web development fundamentals at the Speck Academy in Krizevci, Croatia.
- Mentored junior colleagues on the Agile methodology and software development.
Technologies: JavaScript, TypeScript, Node.js, GraphQL, Redux, Sequelize, PostgreSQL, React, Git, Jest, SQL, Mocha, HTML5, CSS3, Styled-components, Web Development, Front-end, Cypress, HTML, CSS, Education, Responsive Web Apps, APIs, Tutoring, Back-end, Full-stack, Mongoose, Visual Studio Code (VS Code), Software Development, Angular, Vue, Express.js, Web App Development, JSON Web Tokens (JWT), REST APIs, Travis CI, Webpack 4, Responsive Web Design (RWD), A11Y, Mobile-first Design, Bootstrap, Webpack, Figma, JSON, OAuth, React Redux, React Hooks, Unit Testing, E2E Testing, React Router, JSX, React Apollo, Windows Subsystem for Linux (WSL), Full-stack Development, NestJS, REST, Software, Bootstrap 4, Material UI, Data Visualization, Front-end Development, Back-end Development, Web, Integration Testing, Server-side Rendering (SSR), React Query, Software Engineering, ESLint, Linux, Jira, JavaScript Testing, Docker, Containerization, Design, Prisma, Drizzle, tRPC, Accessibility, jQuery, Less, SMACSS, Sass, Progressive Web Applications (PWAs), GitHub, Netlify, Jekyll, Three.js, Redux Toolkit, Chrome Extensions, User Experience (UX), Testing, Web Usability, Minimum Viable Product (MVP), User Interface (UI), Pixel Perfect, Front-end Architecture, Contentful, Educational Portals, Heroku, UI Components, Design Systems, B2B, UI Development, Amazon Web Services (AWS), MySQL, React Testing Library, Web Content Accessibility Guidelines (WCAG), Architecture, Web Architecture, Responsive UI, Web Accessibility, WCAG 2, Communication, SaaS, Responsiveness, Enterprise, RESTFul APIs, Svelte, Test-driven Development (TDD), Databases, Apollo Server, UI Testing, Application State Management, Page Speed Optimization
Transformer Design Engineer
2014 - 2018
Končar Distribution and Special Transformers
- Designed three-phase, oil-filled power transformers (3MVA–120MVA).
- Wrote VBA scripts to automate a few repetitive engineering tasks, which ultimately saved the company time and money.
- Communicated and cooperated with different company departments like sales, mechanical engineering, production, testing, quality assurance, and procurement during product development.
Technologies: MATLAB, Electrical Machine Design, Electrical Engineering, Software Development, Machinery, Industrial & Manufacturing, Windows Subsystem for Linux (WSL), Software, Less, Excel VBA, Visual Basic, Communication, Enterprise
Experience
Data Analytics Product for One of the Top 3 Global Consultancies
I worked as a software developer on a state-of-the-art solution based on machine learning and advanced optimization techniques to support key stakeholders of a large forest industry group in making strategic decisions.
I created an advanced multi-page dashboard with React that has a lot of complex data visualizations. Then, I implemented UI components such as charts, geo maps, tables, and Sankey diagrams with the help of libraries like D3.js, DeckGL, Chart.js, and React (TanStack) Table.
I created an advanced multi-page dashboard with React that has a lot of complex data visualizations. Then, I implemented UI components such as charts, geo maps, tables, and Sankey diagrams with the help of libraries like D3.js, DeckGL, Chart.js, and React (TanStack) Table.
Customized Solution Portal | Volkswagen Group
A modern tool for VW partners to easily remodel VW's commercial vehicles.
I worked as a front-end developer and oversaw the building of the client-side of the app from the ground up to the release phase.
I worked as a front-end developer and oversaw the building of the client-side of the app from the ground up to the release phase.
Audi on Demand | Customer Facing Rental (ABI)
Collaborated and developed premium mobility and car rental service. I worked as a full-stack developer, and some of my responsibilities included
• Implementing new front-end features (SPA).
• Implementing new back-end features (BFF in Java and Spring).
• Reviewing code.
• Performing the role of a site reliability engineer.
• Implementing new front-end features (SPA).
• Implementing new back-end features (BFF in Java and Spring).
• Reviewing code.
• Performing the role of a site reliability engineer.
CONiQ Cloud (IIoT) | Schenck Process
The CONiQ Cloud app is used to monitor the condition of screening machines and vibrating feeders.
The project's overall goal was to build an industrial IoT platform based on AWS services that can partially or entirely substitute the existing monitor solution.
I was a part of a large scrum-based development team in a front-end developer role. My main responsibility was adding new features to the client-side of the application.
The project's overall goal was to build an industrial IoT platform based on AWS services that can partially or entirely substitute the existing monitor solution.
I was a part of a large scrum-based development team in a front-end developer role. My main responsibility was adding new features to the client-side of the application.
DHL Shipping Platform
A mission-critical platform aimed at shippers interested in accessing DPDHL shipping services around the globe.
I worked as a front-end developer, and my primary responsibility was setting up the front end of this greenfield project from the ground up.
I worked as a front-end developer, and my primary responsibility was setting up the front end of this greenfield project from the ground up.
TeamViewer | Web and Native Client
A web app that is used to securely connect and control a remote target device from anywhere.
I worked as a front-end developer in a larger scrum team and implemented new features for the TeamViewer 2.0 UI.
I worked as a front-end developer in a larger scrum team and implemented new features for the TeamViewer 2.0 UI.
Online Education Platform
Developed an online education platform that provides after-school STEM and sports enrichment programs and summer camps for kids.
I worked as a full-stack developer responsible for adding new features to the project's front and back end (RESTful API).
I worked as a full-stack developer responsible for adding new features to the project's front and back end (RESTful API).
Run Tracking App
An app intended for athletes that wish to log their running activities and share them with other users on the platform. It supports two types of users, public and logged-in.
I worked on the front and the back end (RESTful API) of the app.
I worked on the front and the back end (RESTful API) of the app.
Education
2011 - 2013
Master's Degree in Electrical Engineering Systems and Technology
University of Zagreb, Faculty of Electrical Engineering and Computing - Zagreb, Croatia
2008 - 2011
Bachelor's Degree in Control Engineering and Automation
University of Zagreb, Faculty of Electrical Engineering and Computing - Zagreb, Croatia
Certifications
JULY 2023 - PRESENT
NestJS Fundamentals
NestJS
FEBRUARY 2020 - PRESENT
Certified Scrum Master
Scrum.org
Skills
Libraries/APIs
React, Node.js, React Redux, React Router, TanStack Table, React Testing Library, Vue, React Query, REST APIs, Chai, Chart.js, jQuery, AWS Amplify, D3.js, Drizzle, Three.js, MobX
Tools
Git, Webpack 4, Figma, JSX, Jira, JavaScript Testing, Prisma, GitHub, Redux Toolkit, Shadcn, Auth0, Mocha, MATLAB, Mongoose, Webpack, React Apollo, Jekyll, Claude Code, Sequelize, Travis CI
Languages
JavaScript, TypeScript, HTML5, CSS3, HTML, CSS, Python, Python 3, Less, Sass, Excel VBA, GraphQL, SQL, SCSS, Java, Visual Basic
Frameworks
Angular, Redux, Jest, Next.js, Bootstrap, Tailwind CSS, Material UI, Express.js, Cypress, Nuxt.js, NestJS, Deck.gl, Ant Design, JSON Web Tokens (JWT), TYPO3, Ionic 4, React Native, tRPC, Svelte
Paradigms
Responsive Web Design (RWD), Unit Testing, Testing, B2B, Web Architecture, Test-driven Development (TDD), E2E Testing, Microfrontends, REST, Azure DevOps, Search Engine Optimization (SEO), SMACSS
Platforms
Visual Studio Code (VS Code), Web, Netlify, Docker, Vercel, Contentful, Webflow, Linux, Heroku, Amazon Web Services (AWS)
Storage
PostgreSQL, JSON, MongoDB, MySQL, Databases
Other
Software Development, Electrical Engineering, Electrical Machine Design, Styled-components, Web Development, Front-end, Zustand, Responsive Web Apps, Web App Development, Full-stack, A11Y, User Interface (UI), CSS-in-JS, React Hooks, Windows Subsystem for Linux (WSL), Software, Bootstrap 4, Data Visualization, Front-end Development, Software Engineering, ESLint, Accessibility, Single-page Applications (SPAs), Web Usability, Minimum Viable Product (MVP), Pixel Perfect, Front-end Architecture, UI Components, Design Systems, UI Development, Vite, Web Content Accessibility Guidelines (WCAG), Architecture, Responsive UI, Web Accessibility, WCAG 2, Communication, SaaS, Responsiveness, Enterprise, RESTFul APIs, Cursor AI, Tailwind UI, UI Testing, AI Tools, Application State Management, Page Speed Optimization, APIs, Tutoring, Back-end, Dashboards, OAuth, Full-stack Development, FastAPI, Back-end Development, Containerization, User Experience (UX), Educational Portals, WYSIWYG Web Builders, Content Management Systems (CMS), Headless CMS, Apollo, Supabase, AmCharts, Mobile-first Design, Machinery, Industrial & Manufacturing, Storybook, Education, Mobile First, Server-side Rendering (SSR), Integration Testing, Design, Progressive Web Applications (PWAs), Chrome Extensions, OpenAI, Control Engineering, Lexical.js, Tiptap.js, CRDT, WebSockets, AWS App Runner, Artificial Intelligence (AI), Large Language Models (LLMs), Apollo Server
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