Scalable System Design: Design a Contact Tracing System

In this post, I want to address scalable system design and how to grow a system while it’s user base grows. Because talking only about the theory can become boring very quickly, I want to discuss this topic on a practical example. Before I start with the design itself, keep in mind that there is … read more …

Brushing Up My Computer Science Skills – A Deep(er) Dive

This blog post is about Computer Science and my current skills in it. While I started to work on side projects (such as PHPAlgorithms, Keestash or Unread News), I have neglected my theoretical knowledge (and the practice following the theory). I want to brush them up a little and utilize this blog post as a … read more …

Mastering a MySQL 5.7 Migration Successfully

One thing I like at my current employer Check24 is the variety in topics and the trust in me to master them. This motivates me to take my work very serious, but also gives me a lot of responsibility since our products represent Germany’s biggest platform for comparing almost everything. But Check24 is not only … read more …

Converting Roman Numerals To Decimal Integers

Algorithms fascinate me again and again. They seem to be very hard to understand, but once you have practiced enough, you will recognize common patterns. Once you reach the state where you see a problem and can imagine a solution, it seems like that you just adjust the previous algorithm used. Saying this, I am … read more …

Vagrant Getting Started

The last few days, I was busy getting started with Vagrant. Vagrant is a nice tool to create a development environment to ‘just start’ developing. New team members, for instance, do not need to set up, but can simply run ‘vagrant up’ to have a fully configured, ready-to-start environment. Personally, in my case, it is … read more …

Traversing a 2D Matrix

The new years first blog is about algorithms (again😅) – more precisely: 2 dimensional matrices. I want to explore the ways how to find connected 1’s (so called islands) in a 2D array. This problem is also known as the “find the number of islands” or “connected components in an undirected graph“. Disclaimer: I generally use … read more …

How To Simple RBAC

Since I have been asked a few times for a “how to” for my “Role Based Access Control” library, I want to summarize this in a little blog post. Maybe the last one for 2018 🙂 Simple-RBAC ist designed to be lightweight. The main purpose is to grant or deny permissions to users using RBAC. … read more …

Software Engineering, Hacks and Solutions

Do you know the situation where you want to test a little change of a pre-tested code “on the fly” and recognize that it does not work any more? I had this situation several times. Therefore, I decided to create a “flood style” blog post where I want to summarize those moments. This “flood type” … read more …

WebSummit 2018 – Impressions and Observations

Today the 10th WebSummit started in Portugal’s capital Lisbon. More than 70,000 people, including 1,200 referents, 2,000 startups, 1,400 investors and 2,500 journalists from about 170 countries are join the mega event for the next 4 days. Earlier this year, I decided to visit this conference as I was really interested in it. The size … read more …