Note: this article was drafted with AI assistance and reviewed by Softinbit Technology before publishing. It is part of the series The .NET Field Guide .

Decide whether to license MassTransit v9, stay on v8 for now, move to Wolverine, or write the RabbitMQ code yourself.

Part of "The .NET Field Guide". Section: Comparisons.

TL;DR

MassTransit v9 moved to a commercial license requiring runtime keys. If you only publish and consume events, you do not need to blindly pay or panic.

Compare three real paths for the same order-processing flow: keep MassTransit (v8 open source or v9 licensed), migrate to MIT-licensed Wolverine 6, or write lightweight async consumers with RabbitMQ.Client 7.

Complete benchmarks, topology setups, retry/dead-letter policies, and an outbox comparison to pick the right option for your team.

Level: Intermediate · Prerequisites: Basic understanding of message queues and RabbitMQ, ASP.NET Core dependency injection · Reading time: 14 min

Dependabot opened a pull request this morning:…