Why We Removed FluentAssertions from Akka.NET

Akka.NET 1.5.64 removed FluentAssertions from every TestKit package. Here's the full story. FluentAssertions moved from the permissive MIT license to a commercial license in 2025. As the second-largest consumer of FluentAssertions on NuGet, Petabridge had to decide whether to keep distributing a now-commercial dependency to every Akka.NET user who writes tests. We decided not to. In this video I walk through the decision, the open-source philosophy behind it, why keeping Akka.NET free and permissionless under Apache 2.0 is non-negotiable for us, and what it means for your tests going forward (hint: vanilla xUnit assertions). No shade on FluentAssertions. This is about what Akka.NET is, and what Petabridge exists to do. COMPANION BLOG POST: https://petabridge.com/blog/why-akkad... CHAPTERS 0:00 Introduction 1:07 Akka.TestKit and FluentAssertions 2:11 OSS Monetization 3:06 Akka.NET Licensing 4:00 Our Vision for Akka.NET and .NET Open Source 5:52 Petabridge's Mission and Values 7:16 Why We Removed FluentAssertions REFERENCED IN THIS VIDEO Lightbend's Akka license change, and why it didn't change Akka.NET [3:24]: https://petabridge.com/blog/lightbend... The Profound Weakness of the .NET OSS Ecosystem [4:24]: https://aaronstannard.com/the-profoun... RESOURCES Akka.NET 1.5.64 release notes: https://github.com/akkadotnet/akka.ne... "Relicense or Die" - on FluentAssertions going commercial: https://aaronstannard.com/relicense-o... ".NET Open Source: What Happens When the Free Lunch Ends?": https://aaronstannard.com/dotnetoss-f... "The Profound Weakness of the .NET OSS Ecosystem" (2014): https://aaronstannard.com/the-profoun... ---------------------------------------- Learn Akka.NET: https://learnakka.net Akka.NET training & support: https://petabridge.com Phobos - observability for Akka.NET: https://phobos.petabridge.com Akka.NET on GitHub: https://github.com/akkadotnet/akka.net Subscribe:    / @petabridge