Nikola is available for hire

Nikola Stanojevic

Verified Expert in Engineering

Back-end Developer

Location

Belgrade, Serbia

Toptal Member Since

April 25, 2018

Nikola is a talented engineer specializing in full-stack software development. Before moving into consulting, he spent six years working in the mobile communications industry, where he designed and implemented scalable, high concurrency software solutions. Nikola is a supportive and enthusiastic team player dedicated to streamlining processes and efficiently resolving project issues and is willing to take ownership of core components.

Back-end Java Ajax Full-stack SOAP MySQL PHP CSS Linux PostgreSQL Spring Boot Tcpdump Git Agile Software Development Stripe

Portfolio

Old Dominion Transportation Group

Java, Spring Boot, Android, PostgreSQL, MySQL, Amazon Web Services (AWS), iCabbi

Virtual Assets LLC

Spring Boot, React, MySQL, Git, Java, SOAP, Asana

Fast Rope Labs

Back-end, Amazon Web Services (AWS), REST, Redis, PostgreSQL, Python, Play, Java

Experience

Back-end - 10 years Java - 10 years MySQL - 9 years PHP - 8 years PostgreSQL - 6 years Spring Boot - 6 years Payment Gateways - 4 years React - 2 years

Availability

Full-time

Preferred Environment

Git, Linux, IntelliJ IDEA, Jira

The most amazing...

...thing I've done in my career was to work with a team on creating an MVNO (mobile virtual network operator) from scratch over a period of two years.

Work Experience

Software Consultant and Team Manager

2019 - PRESENT

Old Dominion Transportation Group

Managed a team of three developers to design and deliver a taxi service vehicle tracking system for insurance reporting purposes, used by over ten fleets in two countries.
Led a team of three developers, a designer, and a QA on building a Taxi service SMS and credit card payment solution used by more than ten fleets in the United States.
Developed an Android application for credit card processing via Stripe's BBPOS Chipper 2X BT solution.

Technologies: Java, Spring Boot, Android, PostgreSQL, MySQL, Amazon Web Services (AWS), iCabbi

Full-stack Developer

2019 - 2021

Virtual Assets LLC

Built a website that allowed users to trade cryptocurrency by depositing cash in one of the 11,000 participating retailers or via ACH (automated clearing house) and converting them to Bitcoin, Ethereum, or Litecoin.
Integrated with Green Dot's "At The Register" SOAP-based API to facilitate cash deposits.
Implemented Sila's ACH payment API to allow users to deposit their funds directly from their bank accounts.
Implemented Block.io and BitGo APIs to support cryptocurrency transfer between different wallets.

Technologies: Spring Boot, React, MySQL, Git, Java, SOAP, Asana

Java Developer

2018 - 2019

Fast Rope Labs

Developed a near real-time bridge between a custom CRM system and two external CRM platforms: Microsoft Dynamics 365 and Salesforce.
Combined the Salesforce API and SOQL to support data synchronization between the Salesforce platform and the custom CRM system.
Integrated the Dynamics 365 REST API to support synchronization of data between the Microsoft Dynamics 365 platform and the custom CRM system.
Optimized Play Framework by creating a plugin to support executing jobs on multiple, user-defined queues to prevent system congestion caused by long-running tasks.
Speeded up queue processing by 50% per thread by implementing modern concurrency patterns.

Technologies: Back-end, Amazon Web Services (AWS), REST, Redis, PostgreSQL, Python, Play, Java

Back-end Developer

2017 - 2018

Pihinga Ltd

Designed and implemented the entire back-end stack for the company's influence marketing platform. This consisted of database design, building RESTful API interfaces, logging, and testing.
Implemented the PayPal API to the platform to provide subscription payments for members.
Integrated the platform with AWS to provide an advanced user experience when adding and removing offers.
Integrated the platform with the most popular social networks, including Facebook, YouTube, Instagram, Pinterest, and others.
Set up and implemented system scheduling and maintenance processes which helped to make the platform faster and more space-efficient.
Established testing and production environments, including automated testing and deployment.

Technologies: Back-end, Cron, cPanel, Apache, MySQL, PHP

Java Developer

2011 - 2017

Procescom

Designed and developed multiple core modules such as instant messaging, real-time billing, rating, promotion, and customer care for Globaltel MVNO (mobile virtual network operator) over a period of two years.
Developed SMS Gateway: a scalable, failure-resistant, high-concurrency system for routing SMS messages via SMPP and HTTP (Kannel) protocols across many content providers and networks.
Built PromoBox platform—a platform that allows mobile operators to manage and offer special promotions to their customers.
Designed and developed kvib.me universal messaging system—a universal chatting platform via web and USSD (unstructured supplementary service data).
Led a team on the implementation and development of a USSD gateway and USSD menu browser for BH Telecom.

Technologies: Tcpdump, Linux, SOAP, Back-end, Git, REST, SLF4J, PostgreSQL, Spring Boot, Java

Experience

InstaVesti App

I designed and developed the InstaVesti website and Android app, a news aggregation application for the Serbian language. The application uses natural language processing (NLP) to detect similar news articles and combine them to avoid repetition while also using this technology to automatically group news articles into categories.

Globaltel MVNO

https://www.globaltel.rs/

I designed and developed multiple core modules such as instant messaging, real-time billing, rating, promotion, and customer care for Globaltel MVNO (mobile virtual network operator) over a period of two years.

Crypto Dispensers

https://cryptodispensers.com/

I designed and developed a cryptocurrency trading platform that enabled users to deposit funds to their accounts via cash deposits at one of the 11,000 participating retailers or via ACH Bank deposits, and later convert them to a cryptocurrency of their choice such as Bitcoin, Ethereum, or Litecoin.

Skills

Languages

Java, PHP, HTML, CSS, Python, JavaScript

Other

Back-end, iCabbi, Payment Gateways, SOAP, SMPP, Ajax, Full-stack, Front-end, Computer Engineering

Frameworks

Spring Boot, Play Framework, Play, Hibernate

Libraries/APIs

Stripe, PayPal API, SLF4J, React, jQuery, Apache Lucene, Facebook API

Tools

Tcpdump, Git, Apache, Cron, IntelliJ IDEA, Jira, Asana, ActiveMQ

Paradigms

Agile Software Development, Concurrent Programming, REST, Object-oriented Programming (OOP)

Platforms

Amazon Web Services (AWS), Linux, NetBeans, cPanel, Android

Storage

MySQL, PostgreSQL, Redis

Education

2005 - 2009

Bachelor's Degree in Computer Engineering

RAF (Racunarski Fakultet) - Belgrade, Serbia

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