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AutoMapper and MediatR announced shift to a Commercial Model : What you need to know

Marc-Andre Roy

• 3 min read

AutoMapper and MediatR are two extremely popular libraries in the .NET ecosystem, supporting developers’ day-to-day work for many years. Recently, their creator, Jimmy Bogard, announced a major change in how these projects will be managed: they will soon move from a fully open-source model to a commercial licensing model.

This decision raises several important questions: What are the reasons behind this choice? How might it impact development teams? And more importantly, what open-source alternatives are available today for those who want to prepare for a potential transition?

This post summarizes the key points of the announcement, outlines the practical implications, and presents viable alternatives to help you anticipate the coming changes with confidence.

Recap: What Are These Libraries Used For?

AutoMapper
Automates object mapping in .NET (e.g., from Domain models to DTOs), reducing repetitive code and improving the clarity of application layers.

MediatR
Implements the Mediator pattern to enable decoupled communication between components through requests, commands, and events. Commonly used in CQRS-style architectures.

Why This Change?

Jimmy Bogard has been maintaining AutoMapper and MediatR for several years, largely on a volunteer basis. When he was employed full-time, this work was indirectly supported by his employer, allowing him to contribute during working hours. Since transitioning to freelance consulting, that indirect funding no longer exists, significantly limiting the time and resources he can allocate to these libraries.

This new reality has led to a notable decrease in contributions, slowing the pace of bug fixes, improvements, and new features. In the long run, this could threaten the sustainability of the projects, leading to stagnation or even eventual obsolescence.

By adopting a commercial model, Bogard aims to achieve several clear objectives:

  • Provide sustainable funding to support continuous development and long-term improvements.
  • Deliver a more structured and professional support offering, especially for enterprise users.
  • Establish a solid and realistic roadmap with dedicated resources to maintain and grow these widely used tools.

Impact for Users

In the short term, this announcement is not expected to directly affect existing users:

  • Current versions of AutoMapper and MediatR will remain free and available via NuGet.
  • There is no immediate requirement to switch to a paid model.

However, over the medium or long term, some changes may emerge:

  • New features or advanced support may become paid offerings.
  • A clearer distinction between the free and commercial versions may be introduced, with specific benefits reserved for paid users (e.g., priority support, exclusive features, companion tools).
  • A defined commercial licensing model could gradually be implemented, potentially with pricing tiers based on company size or usage type.

Jimmy Bogard has expressed a commitment to being fully transparent throughout this transition. He will communicate the details of the commercial model (pricing, included features, timeline) progressively, giving teams ample time to adapt.

As such, teams that rely heavily on these libraries are encouraged to closely follow upcoming announcements in order to plan proactively for any significant changes in usage.

Open-Source Alternatives to AutoMapper

If you’re considering alternative solutions for object mapping in .NET projects, here are a few options to explore — all of which have shown some recent development activity (at least one commit in the past six months):

Mapster

  • URL: Mapster on GitHub
  • Description: Mapster is a modern, high-performance alternative to AutoMapper. It supports compile-time code generation (via source generators) and offers both explicit and semi-automatic mapping with a high degree of control.
  • Maintenance status: Active. The project is regularly updated, with recent commits (e.g., February 2025).

ExpressMapper

  • URL: ExpressMapper on GitHub
  • Description: ExpressMapper is a lightweight mapping solution based on expression trees, best suited for simple scenarios.
  • Maintenance status: Low activity. The last commit was made several years ago, suggesting that the project is no longer actively maintained.

Manual Mapping or Code Generators

  • Description: Another viable approach is to implement mappings manually or use code generators (such as Roslyn source generators or tools like Fody) to automate part of the process.
  • Pros:
    • Full control and transparency over the generated code.
    • No external dependencies.
  • Cons:
    • More verbose and potentially tedious for complex mappings.

Generative AI-assisted Mapping

  • Description: With the rise of generative AI tools (such as GitHub Copilot or GPT-4), it’s now possible to generate initial mapping code directly from your IDE. This approach offers a hybrid model — combining explicit code control with automation during implementation.
  • Pros:
    • Significantly reduces boilerplate and repetitive code.
    • Integrated into the development workflow.
  • Cons:
    • Still requires developer review to ensure correctness and consistency.

Key Takeaway

There’s no immediate urgency, but this is a significant evolution worth watching — especially if you’re starting new .NET projects that depend on AutoMapper or MediatR. For those looking to reduce their dependency on AutoMapper, Mapster stands out as a viable and actively maintained alternative.

Additionally, generative AI tools like GitHub Copilot or GPT-4 can assist in producing clean, explicit mapping code quickly, offering a hybrid solution that combines automation with full control over your implementation.

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