MediatR

Use one dispatch model for request/response and fan-out notifications

The library supports request/response, commands, queries, notifications, and events. It handles synchronous and asynchronous dispatch and uses C# generic variance, allowing callers to send work without directly referencing a concrete handler.

Sources: [1]

Add handler discovery and cross-cutting behavior through dependency injection

MediatR integrates directly with Microsoft.Extensions.DependencyInjection and scans selected assemblies for request, notification, and stream handlers. Pipeline behaviors, stream behaviors, pre-processors, post-processors, and exception handlers provide extension points for validation, logging, and other cross-cutting work.

Sources: [1]

Fits applications that need explicit use-case boundaries without direct handler dependencies

It is a candidate for web APIs and business applications that want controllers or views to depend on a sender abstraction rather than individual use-case classes. It also fits command/query separation, fan-out domain notifications, and shared validation or auditing pipelines.

Treat it as in-process mediation and review the current licensing model

MediatR provides in-process messaging. It does not replace a broker that transports messages between services, persists them, or retries delivery, so distributed systems need a separate transport and reliability design.

The v14.2.0 README documents license-key configuration and license-warning filtering. Source and binaries are offered under RPL-1.5, with a separate License Agreement offered when software built with them will not be released under those reciprocal terms. Review the distribution model and license obligations before adoption.

Sources: [1][2][3]