From Threads to Async: How Haskell Tames Concurrency

Every month we meet to hang out and talk functional programming.

This month’s speaker is Kelly Brower.

Modern software is inherently concurrent, but the path to managing it has been anything but simple. This talk traces a practical evolution of concurrency models—from shared-state threads and locks, to Software Transactional Memory (STM), and finally to structured asynchronous programming. Using Haskell as a guide, we’ll explore how each step addresses real problems like race conditions, composability, and reasoning about effects. Along the way, we’ll connect these ideas to patterns developers may recognize from other ecosystems (e.g., async/await in Python), while highlighting what makes Haskell’s approach uniquely powerful. This is a beginner-friendly, concept-first talk aimed at developers who have seen concurrency “in passing” but want a clearer mental model—and a sense of where things are headed.

The general schedule is

• 17:30 – socialize
• 17:50 – announcements
• 18:00 – primary talk
• 19:00 – discussion
• 19:30 – hang up

Everyone is welcome – we abide by the Contributor Covenant.