Stateless Authentication using JWT (JSON Web Token)

Currently I work on an implementation for authentication and authorization using Spring Boot, Spring Security, OAuth 2.0 and JSON Web Tokens (JWT). In order to get a good understanding on these topics I found several talks that I’m going to list here.

100% Stateless with JWT (JSON Web Token)” by Hubert Sablonnière. I found it very useful to get a better understanding on using JWTs to create a really stateless authentication architecture.


There is another interesting talk on Stateless authentication with OAuth 2 and JWT by Alvaro Sanchez-Mariscal.


This post will be updated as I find new resources.

Apache Kafka Streams

I’m interested in Apache Kafka Streams and would like share some information on this topic with you. There is a great talk about Stream Processing from Neha Narkhede who co-authored Apache Kafka and is currently a co-founder and Head of Engineering of Confluent.

There is also a good article on Apache Kafka Streams with lots of background information.

[video] – Knowledge is Power: Getting out of Trouble by Understanding Git

Have you ever wondered how git works internally or why git does certain things in a certain way? Recently I found an interesting talk about git’s internals on goto; conference. It explains all the building blocks that you need to understand to better understand git.

Knowledge is Power: Getting out of Trouble by Understanding Git


Programming as Performance

Programming as Performance? This sounds interesting and indeed it is, as you can see in this video by Sam Aaron (a Post-Doc Researcher at the Cambridge University):

He wrote Sonic Pi, a program to enable children and others interested in coding and music to create their very individual sounds using a simple keyboard and a Raspberry Pi.

How to convert a .PDF file to .PNG using Image Magick

ImageMagick is a powerfull tool to manipulate images. If you want to convert a .PDF to an .PNG file use the following command:

convert -verbose -density 300 -trim input.pdf -quality 100 -sharpen 0x1.0 -background white -flatten output.png

Assuming that your pdf is called “input.pdf” and consists only of one page. The above command colors any transparent background white.

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Certified Salesforce Platform App Builder – Part 1: Exam Overview

In order to prepare and pass the Salesforce App Builder Exam I follow the learning path as described in the official “Certified Salesforce Platform App Builder Study Guide“.

But how many questions on each topic have to be answered in the exam? The total number of questions is 60 and the expected number of questions on each topic can easily be calculated:

Overview of exam questions per topic

Topic Weight Questions
Business Logic and Process Automation 27% 16,2
Data Modeling and Management 20% 12
User Interface 14% 8,4
Security 10% 6
Salesforce Fundamentals 8% 4,8
App Deployment 8% 4,8
Reporting 5% 3
Mobile 5% 3
Social 3% 1,8
Total 100% 60

My strategy is to begin with the most important topic with the most questions and work my way down to the end of the list.

This post is the beginning of a series of posts on how I prepared for the exam. This part gave an overview of the topics and their weights. In the next part of I will focus on “Business Logic and Process Automation” in Salesforce and go into more depth.

Stay tuned and stay focused!

Interesting Creative Digital & Internet Agencies

Since several months I work as a Full Stack Software Engineer for Scoop & Spoon, a creative digital & internet agency based in London (UK), Vienna and Graz (Austria). I was wondering which other digital & internet agencies are out there and luckily found an interesting article in the brand eins magazine regarding this topic. The following list is a compilation of interesting agencies out there:

Do you know other interesting agencies? Feel free to comment and point me to your favorites or leave any other feedback.