Adnan Kukuljac, Developer in Berlin, Germany
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Adnan Kukuljac

Verified Expert  in Engineering

Software Developer

Berlin, Germany
Toptal Member Since
October 19, 2017

Adnan is an experienced software engineer with bachelor's and master's degrees in computer science. He has six years of professional experience and has contributed to diverse solutions, from those serving a couple of users to those serving millions of customers worldwide. Adnan's latest accomplishments include software performance improvements and the subsequent reduction of client expenses by $15,000 per week. In so doing, he has collaborated with more than 30 teams.


Zalando SE
MySQL, Amazon DynamoDB, Cassandra, Redis, Java
Acupic (via Toptal)
JavaScript, PHP
Scrappygram (via Toptal)
Amazon Web Services (AWS), PostgreSQL, PHP




Preferred Environment

IntelliJ IDEA, Git, MacOS

The most amazing...

...thing I have developed is Zalando's Product Offer platform, which is the central platform within Zalando.

Work Experience

Software Engineer

2016 - 2019
Zalando SE
  • Implemented a Cassandra token store that served as a temporary solution to solve a Redis issue we had at that time.
  • Improved performance and design issues that led to a 30% reduction in costs for servers.
  • Implemented the tracking of business events, which helped us to measure key metrics and improve stability.
  • Created a newsletter hash login with AES algorithm.
  • Integrated with FedEx and Colissimo services (pickup, point, and return).
Technologies: MySQL, Amazon DynamoDB, Cassandra, Redis, Java

Software Engineer

2018 - 2018
Acupic (via Toptal)
  • Fixed issues in the existing web application and prepare it to go live.
  • Improved code quality by reducing duplicated files and code and introducing a version control system that previous developers didn't use.
  • Implemented necessary changes, which ensured that the application is working smoothly in web-view (mobile application).
Technologies: JavaScript, PHP

PHP Developer

2017 - 2017
Scrappygram (via Toptal)
  • Implemented a class that is responsible for uploading and downloading files to S3 (AWS).
  • Fixed the bug using SendGrid SDK on Heroku (the mbstring extension was missing on Heroku).
  • Created guidelines and a development roadmap.
  • Fixed security issues on an existing implementation.
  • Improved the testing process for the API.
Technologies: Amazon Web Services (AWS), PostgreSQL, PHP

Software Engineer

2015 - 2016
Dilax Intelcom
  • Implemented an algorithm to efficiently generate sensor data (Scala).
  • Contributed to the development of the back end in Java (Spring) for Dilax's people counting software.
  • Participated in developing the front end in AngularJS for Dilax's people counting software.
  • Participated in the knowledge transfer when Dilax Intelcom acquired the company 42Reports, which allowed for a simpler process during the acquisition.
  • Improved two internal software solutions written in Java (Spring).
Technologies: PostgreSQL, Angular, Scala, Java

Software Engineer

2014 - 2015
  • Developed a Hadoop MapReduce for Epinomics, which allowed them to efficiently store DNA sequences in Cassandra.
  • Built a Python pipeline on top of Luigi which allowed the Epinomics team to analyze the data faster.
  • Automated the process of creating a cluster on AWS on top of StarCluster and starting various jobs, which lowered costs and increased efficiency.
  • Developed the back end for Epigenomics web application which is used by Bioinformatics engineers to track analyses of DNA and helped them to analyze the data.
Technologies: Amazon Web Services (AWS), MapReduce, Hadoop, StarCluster, Redis, MySQL, Cassandra, Python, Java

Software Engineer

2013 - 2014
Izum Web
  • Developed a module that interacted with third-party solutions to provide nearest Danish post offices based on ZIP code.
  • Built a module that allows shop owners to easily manage ePay transactions.
  • Implemented a web service to synchronize stock between a physical store and online webshop.
  • Participated in developing various eCommerce websites.
Technologies: PHP

Software Engineer

2012 - 2013
  • Contributed to the development of an algorithm that was able to generate math tasks for kids based on their previous test results.
  • Participated in developing the back-end part of a web application that allows children to test their knowledge and, based on test results, provide exercises for improvement.
Technologies: MySQL, ASP.NET, C#

Contributed to Monaliza Library
Contributed to Monaliza library, an image faker library used to test all sorts of applications when it comes to the use of images.

Android MoneyFlow App

Hobby project - MoneyFlow helps you track and manage your money. Each section is intuitively organized to give you an overall picture of your finances. With this application, you can add and see your expenses very quickly and easily.

Developed this hobby project in order to allow faster and more interesting Q&A sessions after a presentation.

Contributed to a Zalando open-source project.

JS Logger
Contributed to JS logger.

Zalando Lounge

Implemented all catalog related and authentication related topics.


Java, PHP, JavaScript, Scala, Python, C#


Play, Yii 1, Spring, CodeIgniter, Angular, Laravel, Hadoop, ASP.NET, Jasmine


jQuery, Twitter API, Facebook API


IntelliJ IDEA, Git, StarCluster


MacOS, Amazon Web Services (AWS), Android


Cassandra, PostgreSQL, MySQL, MongoDB, Redis, Amazon DynamoDB


Agile Software Development, Concurrent Programming, MapReduce, Kanban, E2E Testing


Computer Science, Development, Open-source Software (OSS)

2012 - 2014

Master's Degree in Computer Science

Faculty of Electrical Engineering, University of Sarajevo - Sarajevo, Bosnia and Herzegovina

2008 - 2012

Bachelor's Degree in Computer Science

Faculty of Electrical Engineering, University of Sarajevo - Sarajevo, Bosnia and Herzegovina

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