Dynamic Module Loading in Blazor WASM vs Interactive SSR

[Claudiu2222]

We’re evaluating Blazor for a large web migration of an ERP system (currently WebForms + DevExpress) and need guidance regarding versioned modules. Our system uses a major.minor.patch versioning scheme, with multiple modules whose behavior may change from patch to patch.

We are considering two hosting models: Blazor WebAssembly and Blazor Interactive SSR. A key question is about dynamic module loading:

• Blazor WebAssembly: Can DLLs be dynamically downloaded and loaded into the runtime after the app is already running, based on the client’s ERP version? Or is the WASM runtime strictly limited to the assemblies packaged at publish time?

• Blazor Interactive SSR: Would it be feasible to dynamically load assemblies and scope them to a specific client circuit based on their ERP version?

The goal is that clients might be using different versions of the ERP system, and depending on their version, we would load only the relevant modules/logic. We want to understand whether the approach we have in mind (dynamic module loading based on the client version) is technically feasible in either Blazor hosting model, and what limitations we might face with runtime assembly loading or scoping per client.

Any pointers, patterns, or references to similar implementations would be appreciated.

[engineering87]

Hello @Claudiu2222,
Blazor WebAssembly is limited for dynamic module loading. You can only lazy load assemblies known at build time. Arbitrary dll loading at runtime isn’t supported, especially with AOT and trimming. This makes per-client versioned modules impractical on WASM.
Blazor Interactive SSR, running on the full .NET runtime, is much more flexible. You can dynamically load modules using AssemblyLoadContext, isolate them per tenant/version, and wire services per circuit through DI.

So:

• WASM: Not suitable for runtime dynamic modules beyond pre-declared lazy loading
• SSR: Supports dynamic loading and per-client scoping and probraly the best fit for your use case