Jacek is a Freelance Data(bricks) Engineer specializing in apache-spark (incl. spark-sql and spark-structured-streaming), delta-lake, databricks, databricks-unity-catalog, and Apache Kafka (incl. Kafka Streams) with brief forays into a wider data engineering space (mostly during Warsaw Data Engineering meetups).

I offer consultancy, courses, workshops, mentoring and software development services.

Contact me at jacek@japila.pl or DM me on Bluesky.

I'm best known by "The Internals Of" online books available free of charge at https://books.japila.pl/.