Waterpark: Transforming Healthcare with Distributed Actors - Bryan Hunter - NDC Oslo 2025

Bryan Hunter explains how HCA Healthcare built Project Waterpark, an enterprise integration platform using Elixir and the BEAM virtual machine.

This talk was recorded at NDC Oslo in Oslo, Norway. #ndcoslo #ndcconferences #developer #softwaredeveloper Attend the next NDC conference near you: ndcconferences.com ndcoslo.com/ Subscribe to our YouTube channel and learn every day: / @NDC Follow our Social Media! facebook.com/ndcconferences twitter.com/NDC_Conferences instagram.com/ndc_conferences/ #architecture #functionalprogramming What happens when you design a system to process real-time healthcare data for millions of patients across 185 hospitals—without ever going offline? Enter Project Waterpark, an enterprise integration platform built at HCA Healthcare using the BEAM (Erlang Virtual Machine) and Elixir. Waterpark ensures continuous availability, handles massive concurrency, and powers life-saving interventions by delivering actionable insights in real time. Since going live in 2020, Waterpark has achieved zero downtime—not even a millisecond. It’s a RAM-based system that doesn’t touch disk or use a database, yet it can survive the loss of an entire data center without losing a message. In this session, we’ll explore Waterpark’s architecture, including: + How the distributed actor model represents millions of patients as long-lived digital twins. + The use of consistent hashing and event-driven algorithms for scalability and fault tolerance. + Challenges faced in building a real-time platform for critical healthcare environments. This isn’t just a technical deep-dive. We’ll share how Waterpark’s real-time signals save lives and ease the burden on caregivers, showcasing the profound human impact of thoughtful system design. Whether you’re curious about Elixir, intrigued by distributed computing, or passionate about leveraging technology for good, this talk will leave you inspired to rethink how your systems handle complexity at scale.