Haoyi Li on Mill, Scala at Scale, Conference Touring and Moving Up the Stack

Haoyi Li discusses the Mill build tool, scaling Scala, his conference tour, and his philosophy on building simple, productive software libraries.

Haoyi Li is a software engineer and a core contributor to the Scala ecosystem. He's built a whole suite of Scala libraries under the com.lihaoyi banner, focusing on simplicity and productivity, as well as the Mill build tool, which he has since expanded beyond Scala to support other JVM tools like Java and Kotlin and experimental support for other things like TypeScript and Android, and promises better performance and user friendliness than Gradle and Maven can ever match. He's also the author of the book Hands-on Scala Programming, which focuses on getting things done with Scala. My own course, Scala Projects, uses Haoyi's book examples as starting points for full-fledged, shippable projects that you can use for yourself or turn into products: rockthejvm.com/courses/scala-projects Timeline 0:00 Intro 1:08 Conference tour 8:20 Haoyi's work on Mill 13:55 What Mill does better than other tools 18:48 Picking a config language 21:53 Scala at scale at Databricks 29:20 How Scala can continue innovating 34:50 Increasing industry adoption of Scala 39:45 Misconceptions about Scala 42:39 Haoyi's experience switching between IC - tech lead - manager - IC 49:39 How Haoyi started programming and why Scala stood out 57:08 Scala differentiators for the future 1:01:05 How Haoyi maintains his OSS library ecosystem 1:06:43 Hands-On Scala Programming: writing, publishing, open-sourcing 1:14:40 Haoyi's current and future contributions to Scala 1:18:16 Discussion on AI agents 1:29:54 Parting thoughts