Nikola Todorovic, Developer in Belgrade, Serbia
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Nikola Todorovic

Verified Expert  in Engineering

Full-stack Developer

Belgrade, Serbia
Toptal Member Since
August 4, 2015

Nikola is an experienced Ruby on Rails developer with over 15 years in software development. He graduated from the best computer science faculty in Serbia. Since then, he's been working on a variety of technologies and companies on projects for the US and EU markets. Nikola has even started his own companies and learned a lot about what is needed for a business to succeed. Currently, his passions are Ruby on Rails, blockchain, and startups.


Innovation Center, Faculty of Mechanical Engineering
Oracle PL/SQL, Oracle, Ruby on Rails (RoR), Ruby, Full-stack, SQL, CSS...
Mondial Software
Ruby on Rails (RoR), JavaScript, PostgreSQL, HTML, CSS, jQuery, Bootstrap...
Traveling Spoon (via Toptal)
Backbone.js, Angular, PostgreSQL, Ruby on Rails (RoR), Ruby, Full-stack, SQL...




Preferred Environment

Sublime Text, Git, Linux, MacOS

The most amazing...

...thing I've built is a payroll algorithm with more than 10,000 bug-free code lines that do payroll for thousands of Serbians at healthcare places.

Work Experience

Software Developer

2012 - 2024
Innovation Center, Faculty of Mechanical Engineering
  • Worked on several projects, some of them pilot projects. The biggest were built for a thermal coal power station in Serbia (TE Kostolac).
  • Built one app using Ruby on Rails, PostgreSQL as a database, and React as a front-end framework. The application shows a map of various businesses in Belgrade and a user can filter them, click on a pin on the map, and see all sorts of information.
  • Created another app using Ruby on Rails and Oracle as a database. It keeps track of more than 7,000 types of spare parts for all kinds of vehicles and keeps track of which vehicle can use which part. Users are able to edit parts and filter them.
  • Wrote procedures in Oracle PL/SQL for one application to calculate the average fuel consumption for excavators, bulldozers, and other vehicles on the open pit.
  • Led the entire development process, including talking to the end customers, building functionalities, testing, deployment, and more.
  • Gained experience in handling a demanding freelance schedule and workload.
Technologies: Oracle PL/SQL, Oracle, Ruby on Rails (RoR), Ruby, Full-stack, SQL, CSS, PL/SQL Developer, jQuery, HTML, Back-end

Full-stack Ruby on Rails Developer

2020 - 2022
Mondial Software
  • Worked on a reporting system for a general ledger accounting software.
  • Integrated AWS Cognito authentication for login purposes.
  • Made reports available in HTML, PDF, and Excel form. PDF was done using LaTeX.
Technologies: Ruby on Rails (RoR), JavaScript, PostgreSQL, HTML, CSS, jQuery, Bootstrap, LaTeX, Back-end, Front-end

Ruby on Rails Developer

2016 - 2018
Traveling Spoon (via Toptal)
  • Worked in an Agile environment with other team members.
  • Implemented many features using Ruby on Rails, Angular, and Backbone.
  • Worked with Stripe, PayPal, Mailgun, and Google Maps.
Technologies: Backbone.js, Angular, PostgreSQL, Ruby on Rails (RoR), Ruby, Full-stack, SQL, CSS, jQuery, HTML, React, APIs, Back-end, Front-end

Ruby on Rails Developer

2016 - 2016
TintManager, LLC (via Toptal)
  • Worked on multiple tasks to add new functionalities to the application.
  • Made significant improvement in application performances.
  • Implemented Handlebars using JSON in a Ruby on Rails application.
  • Implemented a multi-tenancy feature within the Ruby on Rails application.
Technologies: Handlebars, JavaScript, Ruby on Rails (RoR), Ruby, Full-stack, SQL, CSS, PL/SQL Developer, jQuery, HTML, Back-end


2015 - 2016
  • Developed, a startup company, completely by myself.
  • Worked on the back end, front end, and deployment.
  • Set up payment processing for the company with 2checkout.
  • Utilized for cloud-based image storage.
  • Integrated DigitalOcean for the server hosting platform.
Technologies: Ruby on Rails (RoR), Ruby, JavaScript, PostgreSQL, Full-stack, SQL, CSS, jQuery, HTML, Back-end


2013 - 2016
  • Scored a $10,000 investment and joined StartupYard, an accelerator in Prague, Czech Republic.
  • Gained new communication skills, pitching for many VCs and angel investors in Prague, Amsterdam, Split, and Belgrade.
  • Learned about business development, customer development, and startup metrics; having a great team is a key point for success, and being able to communicate well within the team is a must. Building a product is a rewarding and challenging endeavor.
  • Discovered that UX is as important as any other part of building a product, maybe even more important.
  • Developed the application itself into a complex solution ( with v2 currently in progress. It has an API on the back end using Rails, Angular on the front, authentication, authorization, and more.
Technologies: Ruby on Rails (RoR), JavaScript, PostgreSQL, Ruby, Full-stack, SQL, CSS, jQuery, HTML, Back-end

Software Developer

2012 - 2012
Deploy, Inc.
  • Contributed to two projects, one of which was a complex Android app and the other of which was a Java application for Royal Caribbean International.
  • Worked in a team with more than twenty developers, each with a specific assignment.
  • Coordinated between the dev team in Serbia and HQ in NYC, working flexible hours to be available during US business hours.
  • Learned to work under heavy pressure, despite it also being my first Android experience, since we had a very tight deadline.
Technologies: Android, Hibernate, Spring, Java, jQuery, HTML

Software Developer

2011 - 2012
Micro Business Solutions
  • Worked with .NET projects, gaining valuable insight into those technologies.
  • Met and negotiated with domestic clients.
  • Worked on some legacy projects from the '90s and saw firsthand the importance of using new technologies to get the job done much faster and cleaner.
  • Learned some valuable lessons about carefully choosing a working environment where things that I value, like quality and honesty, are valued by the company as well.
Technologies: Windows Mobile, .NET, Microsoft SQL Server, C#

Software Engineer

2009 - 2011
Faculty of Electrical Engineering
  • Created a payroll algorithm with more than 10,000 lines of bug-free code which calculated payrolls for thousands of people at healthcare institutions in Serbia.
  • Worked from day one on a project called Moneo (part of HELIANT system) for which the algorithm was developed.
  • Worked on the core part of HELIANT system, which represents Electronic Health Record systems (EHRs) designed in Java and is used for monitoring the work of doctors as well as keeping records of patients in these health care institutions.
Technologies: Oracle PL/SQL, Oracle, Java, SQL, jQuery


This was a startup founded by myself and developed using Ruby on Rails and PostgreSQL. Worked on back-end, front-end, and deployment. Payments were processed with 2checkout, was used as a cloud image storage, and DigitalOcean was used as a server hosting platform.


A startup founded by me and my friends. It was a service for consumers and businesses who wanted to store their warranties in one place so they won't lose them any more. They could track bought items through their warranty period, report problems, and more. Retailers and manufacturers could use this data to improve their products and gain new customers. We used Ruby on Rails and PostgreSQL for the web application.

Member, Mensa International
Mensa is the largest and oldest high IQ society in the world. You have to score at or above the 98th percentile – the top 2% – on a standardized, professionally administered IQ test. This is typically a score of 130 or more. I have been a member since November 2008.
2007 - 2009

Master's Degree in Computer Engineering

School of Electrical Engineering, University of Belgrade - Belgrade, Serbia

2003 - 2007

Bachelor's Degree in Computer Engineering

School of Electrical Engineering, University of Belgrade - Belgrade, Serbia


Blockchain Academy



Ruby on Rails API, jQuery, Devise, Handlebars, Backbone.js, React, CarrierWave


Notepad++, RSpec, Git, Microsoft Excel, JBuilder, Sublime Text 3, Sublime Text, Apache, NGINX, Redmine, TortoiseSVN, Subversion (SVN), LaTeX


ZURB Foundation, Ruby on Rails (RoR), JSON Web Tokens (JWT), Bootstrap, Bootstrap 3, Factory Girl, Angular, .NET, Spring, Hibernate


HTML, SCSS, CSS, SQL, XML, Ruby, Stored Procedure, PL/pgSQL, JavaScript, HTML5, CoffeeScript, C#, Java


Model View Controller (MVC), Object-oriented Programming (OOP), Test-driven Development (TDD), Database Design, Object-oriented Design (OOD), Unit Testing, Metaprogramming, Scrum, Agile Software Development, Software Testing, Design Patterns


Oracle, DigitalOcean, Linux, Blockchain, MacOS, Windows, Windows Mobile, Android


PostgreSQL, PL/SQL Developer, JSON, Oracle 11g, Oracle PL/SQL, SQLite, Microsoft SQL Server

Industry Expertise

Project Management


Full-stack, APIs, Software Architecture, Lean Startups, Lean Development, Hash, Ajax, Minimum Viable Product (MVP), Back-end, Cloudinary, CanCan, Front-end, Product Development, Payment Gateways

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