Tomasz Lelek has years of experience working with a wide range of production services, architectures, and programming languages. He has designed systems that handle tens of millions of unique users and hundreds of thousands of operations per second, giving him deep insight into what makes software systems fail and how to make them resilient.

Currently, Tomasz designs developer tools at DataStax, a company that builds products around the Cassandra database, helping developers work more effectively with large-scale distributed data.

He is the author of Software Mistakes and Tradeoffs (Manning), a book about making sound engineering decisions, avoiding common design mistakes, and understanding the tradeoffs behind performance, reliability, and maintainability. Through his writing and his work, Tomasz helps engineers reason carefully about architecture and build systems that stand up to real-world scale.