In this post I want to introduce the JOOQ sql domain specific language (DSL) for Kotlin and Java. It is free for open source databases and we will use postgresql in this tutorial. We will write a small app to manage todolists in Kotlin. I will not explain how to setup a postgresql database but there are a lot of tutorials available for several operating systems. Create the database At first we need to connect to our postgres database, add a user and create a database.