Jacek is an IT freelancer who specializes in Apache Spark™, Delta Lake and Apache Kafka (with brief forays into a wider data engineering space — Trino, Dask and ksqlDB — mostly during Warsaw Data Engineering meetups).

He offers software development and consultancy services with very hands-on in-depth workshops and mentoring. Jacek is best known for “The Internals Of” online books that are available free of charge.

Website: https://books.japila.pl/