Robert Deak, Developer in Zagreb, Croatia
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Robert Deak

Verified Expert  in Engineering

React and Node.js Developer

Zagreb, Croatia
Toptal Member Since
January 29, 2019

Robert is a software architect and developer with 10+ years of engineering experience, specializing in React and Node.js for the past four years. While building efficient, maintainable, and fault-tolerant apps, he has worked on every phase of software development, including product user stories, development, testing, and CI/CD pipelines. Robert excels at delivering what clients need and want.


Pfizer - PGS Operations Insights
JavaScript, CSS, HTML, Node.js, React, GraphQL, Docker, Neo4j, REST APIs...
M3G Technology
React, WebSockets, REST, Webpack, Styled-components, TypeScript...
TypeScript, React, React Redux, API Integration, Jest, Figma, HTML, CSS, Sentry...




Preferred Environment


The most amazing...

...thing I've built is a highly scalable messaging service for pushing and pulling client notifications.

Work Experience

Full-stack Developer

2022 - PRESENT
Pfizer - PGS Operations Insights
  • Developed an application for distributing employees' assignments across different divisions depending on availability.
  • Built a Google-like search algorithm for finding data across different data sources.
  • Developed complex interactive data visualization charts.
  • Built an application that dynamically maps vast amounts of data and lets user sort and filter data.
  • Developed an API endpoint for streaming huge XLS documents from the server.
  • Built an application for tracking and verifying molecule cuts feasibility.
Technologies: JavaScript, CSS, HTML, Node.js, React, GraphQL, Docker, Neo4j, REST APIs, Python, FastAPI, PostgreSQL, Elasticsearch, D3.js

Senior React Architect | Developer

2021 - 2022
M3G Technology
  • Developed a front-end app to handle customer communications via SMS.
  • Sliced the complete app design into React components, including image optimizations.
  • Integrated WebSocket and a REST API for handling communication.
  • Debugged and fixed bugs in a legacy Angular application.
  • Made progress toward implementing user notifications for new events.
Technologies: React, WebSockets, REST, Webpack, Styled-components, TypeScript, User Interface (UI), Unit Testing, HTML, GitHub, CSS, Jira, Web API, Web Notifications, HTML5, Event Design, REST APIs

Senior React Developer

2021 - 2021
  • Set up a development server and build process, linting rules (including commit messages), a test suite, storybook, tracing, error handling, and a defined project directory structure.
  • Sliced dozens of Figma designs into React components.
  • Refactored a component library project into TypeScript.
  • Optimized a GitLab CI/CD pipeline and added changelog management.
  • Enhanced a testing suite and set up end-to-end testing with
  • Integrated numerous core business REST API endpoints.
Technologies: TypeScript, React, React Redux, API Integration, Jest, Figma, HTML, CSS, Sentry, GitLab, Release Management, Private NPM Modules, Material UI, React Query, React Hook Form, Storybook, ESLint, ParcelJS, Cypress, REST, OpenAPI, Localization, React Router, Unit Testing, HTML5, REST APIs

React Architect and Developer

2021 - 2021
  • Set up a Next.js project with tests, linting, and a deployment flow.
  • Sliced and implemented the design in Figma for mobile and desktop viewports.
  • Executed an OpenCV algorithm to validate image content before uploading it.
  • Integrated Google Analytics and general user tracking.
  • Implemented a new REST API for handling nicotine test images.
Technologies: React, Next.js, REST, OpenCV, Figma, Google Analytics, API Integration, User Interface (UI), HTML, CSS, GitHub, HTML5, REST APIs

Senior Full-stack React and Node.js Developer

2019 - 2021
Agility Logistics (via Toptal)
  • Assisted in refactoring and redesigning a React application.
  • Implemented core business functionalities on the back end in Node.js and TypeScript.
  • Integrated complex React components, including a quote form and booking form.
  • Assisted in Dockerizing an application with all the dependent services.
  • Helped set up end-to-end tests, integrated them into a CI pipeline, and wrote many tests.
  • Handled API integration with another freight company solution.
  • Implemented numerous GraphQL resolvers, including caching long-term data in Redis.
  • Created Mongo collection repositories in Node.js and TypeScript.
  • Migrated a big chunk of business logic from PL/SQL to Node.js.
Technologies: React Redux, JavaScript, Agile, SQL, Oracle SQL, GitFlow, Oracle PL/SQL, CircleCI, Docker Compose, Docker, API Integration, Jest, Cypress, Styled-components, Figma, Express.js, Apollo Server, React Apollo, GraphQL, Redux, MongoDB, Node.js, React, TypeScript, Redis, Material UI, PL/SQL, Sagas, Redux-Saga, Apollo, React Router, Kibana, Full-stack, User Interface (UI), HTML, CSS, Unit Testing, Atomic Design, Amazon Web Services (AWS), Meteor, Redis Queue, Message Queues

Senior React Developer

2020 - 2020
M3G Technology (via Toptal)
  • Fixed issues by styling Stripe components and wrapping them in Material-UI components.
  • Resolved issues by bundling assets in a custom React setup to match an existing Django app deployment flow.
  • Refactored and removed almost 30% of the codebase, including the removal of unused libraries.
Technologies: React, Stripe, Stripe API, Material UI, Axios, React Router, HTML5

React Architect and Developer

2019 - 2019
Battery Learning, Inc. (via Toptal)
  • Defined the front-end and back-end project structure.
  • Built a custom, Medium-like, Draft.js editor in React.
  • Implemented Firebase Authentication, Cloud Firestore, and firestorage functionalities.
  • Created a SCORM generator (2004 third Edition) in Node.js.
  • Set up the Apollo Client and Apollo cache as local storage instead of Redux.
Technologies: Express.js, JavaScript, GitFlow, Draft.js, SCORM, Firebase, GraphQL, Node.js, React, Apollo, React Apollo, HTML, CSS, GitHub, HTML5

TypeScript Developer

2019 - 2019
  • Integrated the Xero API, Stripe API, and NetSuite (Node.js).
  • Implemented the entire user onboarding process using React.
  • Dockerized Node.js and React applications with all the dependent services.
Technologies: React Redux, JavaScript, SQL, Oracle SQL, GitFlow, SuiteScript 1, NetSuite, Xero API, Stripe API, Docker, Express.js, Node.js, TypeScript, React, Stripe, REST APIs

Senior Java Architect

2009 - 2019
Privredna Banka Zagreb, Intesa Sanpaolo Group
  • Designed and implemented a highly scalable messaging service.
  • Created and implemented several key features into a branch application for corporate clients.
  • Implemented and designed payment processing into an internet banking application.
  • Developed several large batch processes into a retail back-end application.
  • Constructed and implemented an application for processing standing orders.
  • Served on a team focused on integrating PBZ banking solutions with other banks in the Intesa Sanpaolo Group.
Technologies: React Redux, Spring Microservice, Spring MVC, Agile, SQL, Oracle SQL, GitFlow, Oracle PL/SQL, JMS, IBM WebSphere, TypeScript, Angular, React, JavaScript, Jakarta Server Pages (JSP), Spring, Java, Oracle, Spring Boot, Oracle RDBMS, Agile Sprints, Spring JDBC, Spring REST, Spring Data REST, Full-stack, Swagger, Jira, IBM MQ, Message Queues

Front-end Developer

2008 - 2009
  • Implemented several specific UI components for the Advantage platform.
  • Created a tool for tracking component releases and creating a changelog.
  • Assisted with integration testing for several internal systems.
Technologies: Agile, GitFlow, IBM Rational ClearCase, JavaScript, Jakarta Server Pages (JSP), Java

Back-end Developer

2006 - 2008
  • Created a B2B portal for a local brush factory using Apex.
  • Implemented a reporting module for a betting web application.
  • Designed and implemented a salary module within a custom ERP solution.
Technologies: JavaScript, SQL, Apex, Oracle Reports, Oracle Forms, Oracle PL/SQL, Oracle SQL

Lead Web Developer

2002 - 2004
  • Created an eCommerce platform for clients to place orders and track records.
  • Built a ticket reservation platform for a Croatian national theater in Osijek, Croatia.
  • Constructed a content management platform for a local news portal.
Technologies: SQL, CSS, HTML, jQuery, JavaScript, PHP

Our Family Chef

A React application that tracks eating habits and assists in making weekly menus and shopping lists. The user enters the meals they plan to make during the week and their ingredients, and the application tries to balance the menu by ingredient type.

OLTP SQL Optimization in a Retail Banking Application

The application was unresponsive when a user requested a transaction list or account details. I reduced response time from more than five seconds to around 300 milliseconds by identifying and dropping all the unused indexes and rewriting critical SQLs.

Digital Certificate Issuing Service

An Angular application I developed for issuing digital certificates to bank clients. In addition to designing and implementing the application, I integrated it with a certification authority over SOAP services.

Customer Call Center Authorization Service

Banks need additional authorization after a customer enters a recipient account that hasn't been used before. I designed and implemented an authorization service that enables bank officers to identify callers using their personal information.

Billing Application

A billing application I created to enable users to configure a list of services and subscription models using event sourcing. Services can be grouped in a package and offered as a subscription model. Users can also mark a service as free of charge or provide a discount for all users or specific users.

E-invoice Service

A service I designed, developed, and integrated with internet banking. After a user receives an e-invoice within an internet banking platform, they can review it and decide whether to accept or reject it.

Toptal React Academy

The Toptal React Academy is an exclusive learning program that teaches the React framework to select members of the Toptal network. After a month of study, all graduates are tasked with completing a 30-40 hour final project to build and deliver a React app from scratch.

React Form Component
I created a component for handling a form input without any boilerplate code.

Get Me Out of Overdraft

A service for tracking personal income written in React. It alerts users when their spending limit has been reached. The service parses a daily transaction report, categorizing the transactions by type.
1998 - 2002

Master's Degree in Financial Management

Josip Juraj Strossmayer University of Osijek, Faculty of Economics - Osijek, Croatia


AWS Certified Developer – Associate

Amazon Web Services


Toptal React Academy Graduate

Toptal, LLC


Oracle Advanced PL/SQL Developer Certified Professional



Oracle Database 11g: Program with PL/SQL



Oracle Database SQL Certified Expert



ITIL V3 Foundation



React, Node.js, React Redux, Redux Form, RxJS, Spring REST, Redux-Saga, jQuery, JMS, Xero API, Stripe, Stripe API, OpenCV, React Query, React Hook Form, OpenAPI, React Router, Redis Queue, Web API, REST APIs, D3.js


GitHub, Apache Maven, Docker Compose, Redux Thunk, JetBrains, React Apollo, Figma, CircleCI, Oracle Forms, Oracle Reports, IBM Rational ClearCase, Git, Sentry, GitLab, Google Analytics, Webpack, Kibana, Jira, IBM MQ


Express.js, Spring Boot, Redux, Spring MVC, Spring Microservice, Spring, Next.js, Angular, Spring JDBC, Hibernate, Cypress, Jest, Jakarta Server Pages (JSP), Draft.js, Material UI, Swagger


HTML, Java, SQL, JavaScript, TypeScript, GraphQL, CSS, PHP, Apex, SuiteScript 1, HTML5, Python


REST, Agile, Unit Testing, SCORM, Event Sourcing


Oracle, Docker, IBM WebSphere, Firebase, Amazon Web Services (AWS), Meteor, AWS Lambda


Oracle SQL, Oracle PL/SQL, Spring Data, Spring Data JPA, MongoDB, Oracle RDBMS, PostgreSQL, Redis, PL/SQL, Spring Data REST, OLTP, Amazon DynamoDB, Neo4j, Elasticsearch


GitFlow, APIs, Integration, Full-stack, Micro SOA, Atomic Design, Apollo Server, Styled-components, API Integration, NetSuite, Sagas, Release Management, Private NPM Modules, Storybook, ESLint, ParcelJS, Localization, Apollo, WebSockets, Axios, Agile Sprints, Financial Management, ITIL V3 Foundation Certified, SOAP, Authorization, Billing Software, Subscriptions, Online Banking, User Interface (UI), Message Queues, Web Notifications, Event Design, Amazon API Gateway, FastAPI

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