Ivan Mrvelj, Developer in Zagreb, Croatia

Ivan Mrvelj

Software Developer

Zagreb, Croatia
Toptal Member Since
October 25, 2017

Ivan is a full-stack web developer who enjoys solving problems and is passionate about creating high-quality experiences. JavaScript is his primary focus and language of choice for most projects. He enjoys collaborating and working in dynamic environments all the while constantly expanding his knowledge and his ever-growing skillset.

Ivan is available for hire
Hire Ivan


React Native, React, Node.js, AngularJS, Angular, TypeScript, JavaScript
Tellimer Limited (via Toptal)
React, Node.js, React Native, Vue, GraphQL, Apollo, Next.js, Nuxt.js
Magnetic Field BV (via Toptal)
Node.js, React, JavaScript


Zagreb, Croatia



Preferred Environment

Vim Text Editor, Visual Studio Code (VS Code), Git, Linux

The most amazing...

...project I've coded is the front-end of a booking engine that works via cross-domain messaging, thus enabling tour agencies an easy way to sell their tours.

Work Experience

2015 - PRESENT

Lead Front-end Developer

  • Architected and developed the front-end codebase in a modular and scalable fashion.
  • Integrated PayPal, Stripe, and Mercado Pago payment APIs.
  • Created an automated deployment process using Capistrano and CircleCI.
  • Migrated a legacy codebase to ECMAScript 2015+ and TypeScript.
  • Integrated Facebook and Twitter APIs.
  • Developed a Socket.IO Node.js server for handling real-time updates.
  • Implemented unit and end-to-end testing.
  • Mentored junior developers, reviewed code, and managed tasks using Agile methodologies.
  • Developed with PHP and Symfony 3.
  • Acted as the lead developer of a mobile booking app for a tour-and-activity service provider (React Native).
Technologies: React Native, React, Node.js, AngularJS, Angular, TypeScript, JavaScript
2018 - 2021

Front-end Engineer

Tellimer Limited (via Toptal)
  • Performed as one of the core JavaScript engineers on a financial research SaaS platform.
  • Collaborated with the team to build the initial versions of the public-facing and internal apps using Vue.js.
  • Helped with key software architecture decisions and migrated the initial single-page app to a statically generated one, substantially increasing SEO scores and Core Web Vitals.
  • Worked closely with a data analyst and integrated tools to help visualize user journeys, data gathering and reporting.
  • Cooperated in designing and implementing a comprehensive testing strategy, which includes unit, functional and end-to-end tests using Jest, Cypress and Cucumber.
Technologies: React, Node.js, React Native, Vue, GraphQL, Apollo, Next.js, Nuxt.js
2018 - 2018

Freelance JavaScript Developer

Magnetic Field BV (via Toptal)
  • Worked on projects for a digital agency.
  • Mostly focused on a project/tool for social media photo sharing.
  • Developed a product and integrated it with social media APIs.
  • Connected a React app with photo storing services and its API.
  • Optimized the current solution and helped the team address the potential obstacles of using specific libraries or storage APIs.
  • Worked with Google Photos API.
  • Did consulting work in making the app future-proof and optimized in regards to performance.
  • Worked with the Canvas API.
Technologies: Node.js, React, JavaScript
2017 - 2017

Freelance JavaScript Developer

Fetch Agency (via Toptal)
  • Implemented a kiosk application for ordering and managing photo creation orders.
  • Constructed an authentication process and secured the existing API access.
  • Delivered the product to the end platform where it was used (e.g., in grocery shops).
Technologies: Node.js, JavaScript, Angular
2013 - 2015

Freelance Web Developer

  • Designed and developed goal-oriented websites.
  • Implemented web designs.
  • Created landing pages using HTML, jQuery, and Sass.
  • Designed banners and flyers using Adobe Photoshop.
  • Built a CMS for a local extreme sports magazine.
  • Developed a web portal for a local Croatian nonprofit organization.
  • Implemented a rich administration interface for a music webshop using PHP and jQuery.
Technologies: Adobe Photoshop, Content Management Systems (CMS), HTML, Sass, jQuery, JavaScript, PHP



Orioly is a booking and marketing SaaS that helps small tour agencies and activity providers manage their business, optimize costs, and quickly start selling their tours and/or activities online.

I acted as the lead front-end developer on this project. Most of my work consisted of designing and developing the front-end code base.

Orioly | Booking Engine

This booking engine which was created for the platform Orioly enables tour agencies and activity providers a quick-and-simple way to market and sell their tours or activities online by placing a book-now button on their website.

I designed and developed the booking engine from scratch using AngularJS and cross-domain messaging as a way of communicating with the server. I also implemented the following payment gateways: PayPal Adaptive Payments, Stripe, and Mercado Pago.

Orioly | Mobile Booking Application for B2B Users

Orioly is a business system for tour and activity providers, and for that purpose, we built a mobile app which can be used by agents, suppliers and other resellers who want to make additional sales.

This mobile app is a React Native product which provides an option for simple booking on the spot, a scanning voucher, and a way to check reservation status.

I was this project's lead engineer and it was built in less than three months.

Klikkie (Toptal)

Klikkie is an app that enables customers to order quality printed photos in a few clicks.

My main focus was working on the client-side React application—namely, rewriting/restructuring the app using best practices, removing performance regressions, connecting the app to the Google Photos (Picasa) API and doing consulting work.


A small NPM library which generates a random Moment.js object.


My personal GitHub profile page in which you can find my personal projects and OSS contributions.



JavaScript, ECMAScript (ES6), HTML, SCSS, Sass, Less, TypeScript, PHP, GraphQL


Angular, Express.js, Redux, React Native, Hapi.js, AngularJS, Symfony 3, Next.js, Nuxt.js


React, jQuery, Node.js, Vuex, Vue, Lodash, Socket.IO, PayPal API, Stripe API, MercadoPago API, Facebook API, Twitter API


Gulp, Vim Text Editor, IntelliJ IDEA, Mocha, Trello, Webpack, Git, Adobe Photoshop


Single-page Applications (SPA), Content Management Systems (CMS), PayPal, Apollo


E2E Testing, REST, Unit Testing, Agile Software Development


Visual Studio Code (VS Code), Firebase, Linux


MongoDB, MySQL