Davor Badrov, Developer in Zagreb, Croatia
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Davor Badrov

Verified Expert  in Engineering

Software Developer

Zagreb, Croatia
Toptal Member Since
December 12, 2019

Davor is a senior full-stack developer with 9+ years of experience, skilled in crafting scalable and efficient solutions. Proficient in both monolithic and microservice architectures, Davor is a versatile asset to any team and project with a deep understanding of front-end and back-end technologies. With a passion for problem-solving and constant learning, he is the perfect candidate to drive your company's growth.


TSG Global
Elixir, MySQL, PostgreSQL, Amazon Web Services (AWS), React, Vue, JavaScript...
JavaScript, Node.js, Elixir, Phoenix, Express.js, TypeScript, CSS...
Continuous Development (CD), Continuous Integration (CI), Cloud, SQL, ESLint...




Preferred Environment

Docker, Linux, Full-stack, Agile, Git, Software Development, Elixir, Phoenix, JSON, Databases

The most amazing...

...thing I've built is a knowledge-sharing platform used worldwide that drastically improved my client's productivity enabling them to double the yearly profit.

Work Experience

Full-stack Developer

2021 - PRESENT
TSG Global
  • Worked on the admin and customer portals and rewrote them from Vue 2 to React/TypeScript. Introduced CI/CD for the front end via GitHub Actions.
  • Worked on the VoIP stack and relevant integrations. Introduced new VoIP providers and implemented custom call logic into the stack.
  • Expanded the functionality of the Elixir back end and wrote a couple of new Elixir microservices.
Technologies: Elixir, MySQL, PostgreSQL, Amazon Web Services (AWS), React, Vue, JavaScript, TypeScript, RabbitMQ, Docker, Kubernetes, Microservices Architecture, GraphQL, APIs, SendGrid, Email Delivery, Email, Node.js, GitHub, CI/CD Pipelines, Front-end, HTML, Responsive Web Design (RWD), Web Development, Websites, PHP, HTML5, Software Architecture, API Integration, Architecture, Agile, Contentful, Git, Netlify, Software Development, Vuex, Payment APIs, Tailwind CSS, Cloud, Single-page Applications (SPA), Test Automation, Linux, Phoenix, Code Review, Telecommunications, Stripe, eCommerce, eCommerce Development, Functional Programming, JSON, Databases, Amazon S3 (AWS S3), Data Visualization, Back-end, API Development

Full-stack Developer

2017 - PRESENT
  • Developed a site for selling electric scooters. It had headless eCommerce and CMS integrations. Based on Gatsby, it integrated with Calendly, BigCommerce API, Salesforce, and Contentful. It was fully responsive with multiple localizations.
  • Built a Node.js-based library, which acted as middleware for Express.js and Koa, that automatically captured user errors and sent them to a platform that aggregated and visualized them.
  • Created the front end of an invoice management app written in React; it was fully responsive and had a lot of custom inputs and dynamically generated pages.
Technologies: JavaScript, Node.js, Elixir, Phoenix, Express.js, TypeScript, CSS, Responsive Design, SQL, PostgreSQL, CI/CD Pipelines, Payment APIs, BigCommerce API, BigCommerce, CSS-in-JS, Gatsby, Netlify, Tailwind CSS, Vue 2, Single-page Applications (SPA), Koa, Linux, Code Review, Shopify, Next.js, Stripe, Material UI, Amazon Web Services (AWS), NoSQL, Svelte, Maps, eCommerce, eCommerce Development, Functional Programming, Supabase, Firebase, JSON, Databases, Amazon S3 (AWS S3), Data Visualization, Back-end, API Development

Software Engineer

2019 - 2020
  • Contributed to extracting common functionalities from a legacy system into reusable microservices.
  • Created an automated CI/CD pipeline for one of the services on code push. The pipeline runs unit tests, E2E tests, and code quality tools. The build would trigger, producing a deployable artifact automatically deployed to the Azure Cloud.
  • Created a new service abstracting away the old legacy system with a vastly simplified UI and behavior. The idea is that eventually, all the legacy parts are removed as they're being replaced.
  • Worked on a system with abstractions, enabling it to connect to different legacy systems through a unified core and UI.
Technologies: Continuous Development (CD), Continuous Integration (CI), Cloud, SQL, ESLint, E2E Testing, ECMAScript (ES6), Webpack, Unit Testing, HTML, Microservices, Front-end Development, Azure, Babel, React, REST APIs, Node.js, Express.js, Sass, CSS, JavaScript, GraphQL, Docker, Azure Cloud Services, Vue, PostgreSQL, Microsoft SQL Server, Phoenix, Elixir, Full-stack, APIs, CI/CD Pipelines, Front-end, Responsive Web Design (RWD), Web Development, Websites, HTML5, Software Architecture, API Integration, Architecture, Agile, Git, Software Development, Vuex, Vue 2, Microservices Architecture, Single-page Applications (SPA), Test Automation, Linux, Code Review, Material UI, NoSQL, Maps, Functional Programming, JSON, Databases, Data Visualization, Back-end, API Development

Full-stack Developer

2015 - 2019
Kanban (KNB_)
  • Contributed as part of a team that made a huge enterprise app for our biggest client, which is being used worldwide by the client's employees. The client's profits increased twofold after one year of using the platform.
  • Scored a major client for the company by delivering a time-critical mobile app with React Native covering iOS and Android within one month. The app had a back end integrated with the client's Odoo system.
  • Led a team of five developers in the development of an enterprise platform.
  • Made a web app for a country-wide promotion game with prizes for one of the largest beer distributors in the country.
  • Optimized a number of large SQL reporting queries. The execution time went down from a couple of minutes to one to two seconds. Sometimes it would be a subsecond.
  • Reduced the complexity of an enterprise platform by proving that a graph database (Neo4j) can be replaced by a couple of JSON definitions and several functions that led to significant code simplification and simplified development deployments.
Technologies: Single-page Applications (SPA), SQL, ESLint, E2E Testing, ECMAScript (ES6), Webpack, Unit Testing, HTML, Responsive Design, Front-end Development, Babel, React, REST APIs, Express.js, Sass, CSS, React Native, Elasticsearch, Redis, NGINX, MongoDB, MySQL, Angular, Node.js, JavaScript, Full-stack, APIs, Less, CSS3 Animation, Mailchimp, Email Delivery, Email, GitHub, CI/CD Pipelines, Front-end, Responsive Web Design (RWD), Web Development, Websites, HTML5, Software Architecture, Architecture, Agile, Git, Web Scraping, Software Development, Data Scraping, SendGrid, Test Automation, Linux, Code Review, Material UI, NoSQL, Maps, eCommerce, eCommerce Development, JSON, Databases, Data Visualization, Back-end, API Development, Chrome Extensions

Front-end Developer

2014 - 2015
  • Created a photo and video contest web app for a US startup. Users could upload photos and videos and participate in contests where the best upload would get prizes. The app was made with scalability in mind.
  • Contributed as a part of the team that developed a new webshop app for a large retailer in Croatia.
  • Made a tablet app with a custom CMS back end for the Croatian branch of Allianz, the insurance company. We migrated all the insurance sales documents to a digitalized format so they could keep up-to-date via the CMS.
  • Created a number of responsive web apps and pages.
Technologies: Single-page Applications (SPA), Gulp, Grunt, ECMAScript (ES6), Webpack, Responsive Design, Front-end Development, Babel, React, REST APIs, Express.js, Sass, Node.js, MySQL, PHP, CSS, HTML, JavaScript, Full-stack, APIs, Less, CSS3 Animation, GitHub, Front-end, Responsive Web Design (RWD), Web Development, Websites, HTML5, Architecture, Agile, Git, Software Development, Redux, NoSQL, Maps, JSON, Databases, Data Visualization, API Development

Tesla's Microservice System

I upgraded and improved an existing React/Node.js microservice which acted as a front end for a third-party system. It was part of a microservice system running on Kubernetes.

The code was built and deployed using a CI/CD pipeline based on Docker containers.

The app communicated with another microservice and had real-time updates with UI refreshing when data in the back end changed.

My responsibilities were to improve the existing system design, fix several issues, and turn the app out of a legacy state into a more modern system. I also proposed a number of changes to improve UX and fix eventual consistency issues that might occur in the system.


I worked as a full stack developer on their React/Redux-based front-end app with Elixir microservices in the back end. It used GraphQL for client-server communication.

I led the front-end development, rewrote and simplified their front-end implementation, fixed the Redux usage patterns, and introduced testing.
I've created an automated CI/CD pipeline based on GitHub actions which would run checks and deploy the app if it passed the linting and tests.
I was also doing integrations in the back end, mostly GraphQL/client app-facing ones.

I also Dockerized some back-end apps and wrote Docker-compose scripts to simplify development. Developers needed to run a Docker-compose up and start their apps instead of installing and managing all the required infrastructure.

Atheneum Enterprise Platform

A knowledge-brokering platform used worldwide in the client's offices, specifically in China, Pakistan, Germany, UK, US, and Chile. The idea is to connect clients who need a job done and experts on the platform. The platform has a vast base of engineers worldwide, with all the experts within their fields.

The platform was built using React, Node.js, MySQL in a master-slave configuration, ElasticSearch, Redis. It also has a custom Chrome plugin.

In production, three app instances were load-balanced to handle the load properly.

It has three different sub-apps: for company employees, for clients, and for experts, which were organized in a micro front-end setup.

The app was running almost 24/7, with super short deployment downtimes. Sometimes deployments were handled with no downtime whatsoever.

Allianz Insurance Sales System

A CMS and a tablet app that enabled the Allianz insurance sales to digitalize all their documents, charts, and tables, have them online, and change them as needed.

The app on the tablet was highly animated and eye-candy focused. It would cache the content locally and sync when connected online.

By relying on MS installers and automation, we enabled the client to install the app on thousands of tablets in a single click.

GCP Tenant App

A React Native iOS and Android app for a real estate company that rents apartments and objects. It has several functionalities to offer their tenants easier apartment maintenance, access to emergency contacts, rent-paying, track updates in their neighborhood area, new apartment search, etc.

The back end was a Node.js app with MySQL. It used the client's Odoo platform to sync data between the systems.

Asolvi Service Management Platform

A platform that is an abstraction of an old legacy system for field service management. It's part of the initiative to reduce maintenance costs for the company since it has a 20-year-old legacy system that it looks to retire.

It was decided to split the monolith platform into microservices. We call it "strangling the monolith." We created two microservices written in Elixir and using PostgreSQL, which communicated with the old platform and extracted core pieces of functionality to it.

The app has a CI pipeline to build Docker images automatically when new code is pushed. The cloud servers were linked to the Docker repository and were automatically redeployed when new versions of images tagged as "stable" were created.

Tweaks were made so the microservices could run on the cloud using Azure App Service and on-premise, specifically on Windows Server and leveraging IIS.

For Windows Server, it was integrated with a custom-made installer so system admins could just run the installer and click through it to set up their whole system without much manual intervention needed on their side.

Karlovacko Beer Promotion Game

A countrywide game with prizes where, on bottle caps, you would find codes and enter them in the web app and could win different prizes. There were millions of codes generated and printed on bottle caps as a part of the promotion.

The app used React, Node.js, MongoDB, and SASS for styling. It was running for a few months.


I was a full-stack developer, mostly doing the back end in Elixir and with PostgreSQL for two-way data syncing between PostgreSQL and Airtable. I also worked on solving multi-tenancy in PostgreSQL securely, spinning up DB instances dynamically when clients onboard.

TSG Global Platform

A telecom platform providing voice, SMS, and MMS transport and supporting services. It has a microservice architecture written mostly in Elixir and a number of UI apps in React (new ones), Vue (old ones), and TypeScript. Everything was containerized via Docker, and it runs in a Kubernetes cluster.

I was a full-stack engineer responsible for maintaining the old services and developing new ones. I wrote a number of new Elixir services, maintained a few old ones (some in PHP and VB.NET), and wrote two new portals using React and TypeScript. I also wrote a number of CI/CD pipelines: one was for Elixir, a rewrite of the old one to provide support for newer Elixir versions, and two were for React to build and deploy code via GitHub Actions automatically. I also maintained, debugged, and automated parts of the Voice stack.

Advalyze - Unu Scooter

A scooter sales and leasing platform based on headless eCommerce integration using BigCommerce and CMS integration using Contentful. It was developed using Gatsby and React for statically built sites. It uses Netlify for deployments and hosting and Contentful for CMS content.

The BigCommerce purchasing flow was fully customized and integrated into SalesForce via its API to better track leads.


SQL, JavaScript, CSS, Sass, HTML, Elixir, TypeScript, HTML5, GraphQL, ECMAScript (ES6), Less, PHP


Express.js, Koa, Phoenix, React Native, Next.js, Tailwind CSS, Redux, Material UI, Angular, Svelte


Node.js, REST APIs, React, API Development, Vue, Stripe, Vue 2, BigCommerce API, Vuex


SendGrid, Git, GitHub, Webpack, Gulp, Grunt, Babel, Mailchimp, NGINX, RabbitMQ


Unit Testing, Agile, Test Automation, E2E Testing, Responsive Web Design (RWD), Functional Programming, Microservices, Continuous Integration (CI), Continuous Development (CD), Microservices Architecture


JSON, Databases, Amazon S3 (AWS S3), MySQL, PostgreSQL, NoSQL, Microsoft SQL Server, Azure Cloud Services, Elasticsearch, Redis, MongoDB, SQL Server 2012


Responsive Design, Front-end Development, Single-page Applications (SPA), Full-stack, APIs, Front-end, Web Development, Websites, API Integration, Software Development, Code Review, Maps, Back-end, CI/CD Pipelines, CSS3 Animation, Email Delivery, Email, Software Architecture, Architecture, Web Scraping, Data Scraping, Airtable, Payment APIs, Data Visualization, Chrome Extensions, Cloud, ESLint, Gatsby, CSS-in-JS, eCommerce, eCommerce Development, Supabase


Azure, Linux, Amazon Web Services (AWS), Docker, Contentful, Netlify, BigCommerce, Visual Studio Code (VS Code), Kubernetes, Shopify, Firebase

Industry Expertise


2012 - 2014

Master's Degree in Computer Science

Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture - Split, Croatia

2009 - 2012

Bachelor's Degree in Computer Science

Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture - Split, Croatia

MARCH 2023 - MARCH 2026

AWS Certified Cloud Practitioner

Amazon Web Services

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