Custom model binders?

Short answer: Use a custom model binder when default binding doesn’t work (e.g., custom formats, headers). public class CustomBinder : IModelBinder {

Example code

public Task BindModelAsync(ModelBindingContext context) { // Custom logic here }
} Register with [ModelBinder] or globally in Startup.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.