MediatR

MediatR, the popular in-process messaging library for .NET, has officially launched its commercial edition on July 2, 2025. Creator Jimmy Bogard announced the move for both MediatR and AutoMapper, transitioning the projects to his new company, Lucky Penny Software, to ensure their long-term sustainability. The MediatR GitHub repository is now located at LuckyPennySoftware/MediatR.

Why the Change?

In his announcement blog post, Bogard explains that the decision stems from a shift in his professional life. Since transitioning from Headspring (where his OSS work was directly sponsored) to solo consulting five years ago, his time available for maintaining and enhancing these open-source projects has significantly diminished.

"Taking time to see how things have been going on all fronts, I had a bit of a shock looking at my OSS work. I realized that model is not sustainable for the long-term success of these projects... I need to be able to pay for my time to work on these projects, and get direct feedback from paying clients..."

- Jimmy Bogard (Source)

He emphasizes that OSS was never just a hobby and that this move is necessary to fund real work on the projects, build communities, and respond to user needs more effectively.

Licensing and Pricing

MediatR now follows a dual-license model: the Reciprocal Public License 1.5 (RPL-1.5) and a commercial license. New versions, starting with MediatR v13.0, are released on NuGet under this new agreement.

The commercial pricing is based on team size, with tiers for Standard (1-10 developers), Professional (11-50), and Enterprise (unlimited). A free Community edition is available for smaller companies (under $5M revenue), non-profits, educational use, and non-production environments, similar to AutoMapper's offering. A license key is required for commercial use. For full details, visit the official MediatR website.

Previous versions of MediatR remain under their original MIT license and have been archived for public access.

Community Reaction to Initial Announcement

The reaction on platforms like GitHub Discussions has been notably calmer compared to the controversies surrounding libraries like Moq or FluentAssertions. Many developers expressed understanding and support for Bogard's decision, acknowledging the effort required to maintain widely used OSS projects.

However, some users on Reddit unearthed a comment Bogard made just two months prior, stating he would "never commercialize MediatR.":

• Do you think MediatR nuget will also become commercial just like fluentAssertions?

• Jimmy: Nah never. You can print it on a shirt "I will never commercialize MediatR". And I will sign it. With like, splatter paint or something.

While acknowledged as potentially poor timing, the overall sentiment seems less heated than in previous cases.

Open Source Alternatives

The .NET ecosystem offers several alternatives to MediatR:

1. Mediator:

   • A high-performance implementation leveraging .NET source generators for better performance, AOT compatibility, and build-time error checking.
   • API is similar to MediatR but with deviations for performance gains (e.g., avoiding closure allocations).
   • Relies on Microsoft.Extensions.DependencyInjection.
   • Nick Chapsas provides a video comparison: Using MediatR in .NET? Maybe replace it with this

2. Brighter:

   • An established FOSS library predating MediatR, serving roles similar to both MediatR and Mass Transit (with workflow features planned).
   • Explicitly committed to remaining FOSS due to its Contributor License Agreement (CLA).

Conclusion

MediatR's move to a commercial model under Lucky Penny Software is now official, securing a path for its continued development. The dual-license model, with its free community tier, means many developers can continue using MediatR without cost. Larger teams will need to factor in licensing costs or explore alternatives like the source-generator-based Mediator or the more feature-rich Brighter library.

Links and References

• Jimmy Bogard: AutoMapper and MediatR Commercial Editions Launch Today
• MediatR Official Site: https://mediatr.io/
• Jimmy Bogard: AutoMapper and MediatR Going Commercial
• GitHub: LuckyPennySoftware/MediatR
• GitHub (old repository): jbogard/MediatR
• GitHub: AutoMapper and MediatR going commercial (Discussion)
• Reddit: MediatR going commercial?
• Reddit: Do you think MediatR nuget will also become commercial?
• Alternative: Mediator
• Alternative: Brighter
• YouTube: Nick Chapsas - Using MediatR in .NET? Maybe replace it with this