Publication
Ruby Metaprogramming Is Even Cooler Than It Sounds
https://www.toptal.com/developers/ruby/ruby-metaprogramming-cooler-than-it-sounds
Nikola is currently unavailable
Nikola Todorovic
Verified Expert in Engineering
Full-stack Developer
Belgrade, Serbia
Toptal member since August 4, 2015
Bio
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.
Portfolio
FullScript - FSLV Holdings LLC
Ruby, TypeScript, GraphQL, React, Iterable, Full-stack, Ruby on Rails (RoR)...
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...
Experience
- PostgreSQL - 14 years
- JavaScript - 14 years
- Ruby - 12 years
- Full-stack - 12 years
- Ruby on Rails (RoR) - 12 years
- Cryptocurrency - 8 years
- React - 1 year
- AI Agents - 1 year
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
Senior Back-end Ruby Developer
2025 - 2025
FullScript - FSLV Holdings LLC
- Contributed to healthcare platform migration project, transferring practitioners and patients from acquired RUPA Health application into Fullscript, implementing OAuth flows and user activation features across multiple user types.
- Implemented GraphQL mutations and queries for migration workflows, collaborating with the front-end team to support client-server communication requirements and ensure efficient data fetching patterns.
- Leveraged AI-powered development tools (Claude) throughout the development lifecycle to accelerate code reviews, debug complex issues, and generate test coverage, improving development velocity and code quality.
- Built an email notification system using the Iterable service for order confirmations and refund processing workflows, implementing event-driven architecture to deliver personalized transactional communications to end users.
Technologies: Ruby, TypeScript, GraphQL, React, Iterable, Full-stack, Ruby on Rails (RoR), Git, RSpec
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, JavaScript, PostgreSQL, Git, Linux, API Integration
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, Redis, PSQL, Web Development, Database Design, Ruby, Full-stack, Git, Linux, Docker, Redis Cache
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, CRUD, Web Development, JavaScript, Git, Redis, RSpec, Linux, API Integration, Docker
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, Web Development, PostgreSQL, Git
CEO
2015 - 2016
Phixio
- Developed Phix.io, 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 Cloudinary.com 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, Web Development, Git
CEO
2013 - 2016
Warrantly
- 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 (Warrant.ly) 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, Git
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
Experience
Phixio
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, http://cloudinary.com was used as a cloud image storage, and DigitalOcean was used as a server hosting platform.
Warrantly
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
http://www.mensa.orgMensa 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.
Education
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
Certifications
JUNE 2018 - PRESENT
Blockchain Academy
Toptal
Skills
Libraries/APIs
Ruby on Rails API, jQuery, Devise, Handlebars, Backbone.js, React, CarrierWave, daisyUI
Tools
Notepad++, RSpec, Git, Microsoft Excel, JBuilder, Sublime Text 3, Sublime Text, Apache, NGINX, Redmine, TortoiseSVN, Subversion (SVN), LaTeX
Languages
HTML, SCSS, CSS, SQL, XML, Ruby, Stored Procedure, PL/pgSQL, JavaScript, HTML5, CoffeeScript, C#, Java, TypeScript, GraphQL
Frameworks
ZURB Foundation, Ruby on Rails (RoR), JSON Web Tokens (JWT), Bootstrap, Bootstrap 3, Factory Girl, Angular, .NET, Spring, Hibernate, Tailwind CSS
Paradigms
Model View Controller (MVC), Object-oriented Programming (OOP), Test-driven Development (TDD), Database Design, Object-oriented Design (OOD), Unit Testing, CRUD, Metaprogramming, Scrum, Agile Software Development, Software Testing, Design Patterns
Platforms
Oracle, DigitalOcean, Linux, Blockchain, Docker, MacOS, Windows, Windows Mobile, Android, Iterable
Storage
PostgreSQL, PL/SQL Developer, JSON, Oracle 11g, Oracle PL/SQL, PSQL, SQLite, Redis, Redis Cache, Microsoft SQL Server
Industry Expertise
Project Management
Other
Full-stack, APIs, Software Architecture, Lean Startups, Lean Development, Hash, Ajax, Minimum Viable Product (MVP), Back-end, Web Development, Cryptocurrency, API Integration, Cloudinary, CanCan, Front-end, Product Development, Payment Gateways, Retrieval-augmented Generation (RAG), AI Agents, Tailwind UI
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