Adnan Kukuljac, Software Developer in Berlin, Germany
Adnan Kukuljac

Software Developer in Berlin, Germany

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.
Adnan is now available for hire




Berlin, Germany



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.


  • 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.

  • Fahrschein

    Contributed to a Zalando open-source project.

  • JS Logger

    Contributed to JS logger.

  • Zalando Lounge

    Implemented all catalog related and authentication related topics.

  • Microservice Communication: A Spring Integration Tutorial with Redis (Publication)
    Spring Integration enables lightweight messaging within Spring-based applications. In this article, Toptal Java Developer Adnan Kukuljac shows how Spring Integration with Redis makes it easy to build a microservice architecture.


  • Languages

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

    Play, Yii 1, Spring, CodeIgniter, Angular, Laravel, Hadoop, ASP.NET, Jasmine
  • Libraries/APIs

    jQuery, Twitter API, Facebook API
  • Tools

    IntelliJ, Git, IntelliJ IDEA, StarCluster
  • Platforms

    MacOS, Amazon Web Services (AWS), Android
  • Storage

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

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

    Computer Science, Development, Open-source Software


  • Master's Degree in Computer Science
    2012 - 2014
    Faculty of Electrical Engineering, University of Sarajevo - Sarajevo, Bosnia and Herzegovina
  • Bachelor's Degree in Computer Science
    2008 - 2012
    Faculty of Electrical Engineering, University of Sarajevo - Sarajevo, Bosnia and Herzegovina

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