Senior Java Developer

8/2020 – 6/2021

My time in Playtika was spent on the World Series of Poker project and revolved around two development cycles.

The first one involved migrating the current AWS cloud infrastructure on premise, which meant moving terabytes of data from our SQL/NoSQL databases. That was achieved using microservices as well as established solutions such as StreamSets resulting in minimal impact on the performance of the game.

The second challenge, was splitting the live monolithic system into a event driven, reactive, microservice architecture, extracting each functionality and rebuilding it using technologies such as Spring WebFlux and Apache Kafka.

Tech Stack:
- Architecture: hybrid - monolith + microservices.
- Backend: Java 8/11, Spring Boot, Spring Data, Spring WebFlux, Spring Cloud.
- Database: AWS DynamoDb, AWS AuroraDB, Aerospike, Mariadb.
- Caching: Redis, Memcached.
- Messaging: Apache Kafka.
- Testing: JUnit, Mockito, TestContainers.
- Cloud/containerization: AWS, Kubernetes, Docker.
- Alerting: ELK stack.
- CI/CD: TeamCity.
- Libraries: Lombok, Log4J, Slfj4J, MapStruct, SonarQube.
- Tools: Lenses, Swagger.

Java (allg.)

1/2020 – 8/2020

At Endava, I worked on administrative platform focused on integrating multiple systems with the aim of providing a unified image over the logistics of an order, from placement to delivery. This was done by building an MVP that encapsulated the main business flows/functionalities, with special focus given towards creating a solid base structure for future developments.

Tech Stack:
- Architecture: microservices.
- Backend: Java 11, Spring Boot, Spring Data, Spring WebFlux, Spring Cloud.
- Database: Azure CosmosDb.
- Caching: Redis.
- Messaging: Azure Event Hubs.
- Testing: JUnit, Mockito.
- Cloud/containerization: Kubernetes, Docker.
- Libraries: Lombok, Log4J, Slfj4J, MapStruct, SonarQube.

Java (allg.)

5/2016 – 12/2019

My time at Tremend Software Consulting was split among four projects. The first was an e-commerce platform where the architecture was based on microservices. My team developed an internationalization and customization service which enabled editors to translate and add content to the website. Also a media service was developed to enable asset management – mainly, cropping/storing images. Data fetched via a REST API was presented in an AngularJs application.

Next followed an internet banking solution. My role involved coding custom AngularJs widgets for the Backbase CMS and, also, developing the backend microservices which connected to the bank systems, aggregated and exposed data through REST APIs.

The third project I worked on a was multi-site, e-commerce platform built on top of the Magnolia CMS and Broadleaf Ecommerce. My job involved building an order fulfillment(checkout) microservice using Spring Boot, integrating the Adyen payment platform, accommodate the UPS Address Validation and Rating APIs, integrating the 2 platforms as well as the order fulfillment microservice (via Swagger generated libraries for client/server).

The last project I was involved in was an admin interface for marketplace platform aiming to automate the processes revolving vendor management and financial reporting. Architecture wise, we were using Spring Boot microservices that communicate through Apache Kafka pub/sub model. The CI/CD process is handled via Bamboo which builds and pushes Docker images into Google Cloud Repository, from which they are deployed and orchestrated though Kubernetes on the GCP.

Tech Stack:
- Architecture: microservices.
- Backend: Java 8/11, Spring Boot, Spring Cloud, Spring Data, Netflix Stack, PHP, Symfony.
- Database: MySQL, PostgreSQL.
- Caching: Redis.
- Messaging: RabbitMQ, Apache Kafka.
- Testing: JUnit, Mockito.
- Cloud/containerization: Kubernetes, Docker.
- CI/CD: Bamboo, Wercker, Jenkins.
- CMS: Magnolia CMS.

Java (allg.)

7/2013 – 5/2016

As part of the job, my main responsibilities were:
- analyzing business requirements, proposing technical solutions and implementing them.
- optimizing the application performance and refactoring the code to improve the quality.
- monitoring the application at the service level (MySQL, MongoDB) and identifying the issues/bottlenecks.

The project I worked on was a dating application. Some of the more interesting implementations I took part in are:
- registration process using 3rd party integrations: Facebook, Gmail and Yahoo
- users, events and transaction monitoring using Google Analytics.
- developing features for the app’s messaging system (alongside with a restriction system at the conversation level) plus integrating with RabbitMQ to persist the messages.
- implementing a friend referral system based on the email address and a bonusing algorithm for each invited friend.
- building a progressive email sending system based on priorities set for distributing a certain volume per IP address.
- developing an application that funnels users into the parent dating site.

Tech Stack:
- Architecture: monolith.
- Backend: PHP, Symfony 2, Zend Framework.
- Frontend: Twig, HTML, CSS, jQuery, PrototypeJs.
- Database: MySQL, MongoDb.
- Caching: Redis, Memcached.
- Messaging: RabbitMQ.
- Other: ElasticSearch.

Software Architektur / Modellierung