# IGrainCallContext.SourceId

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.core.abstractions/orleans.igraincallcontext/) | [Properties](/orleans/docs/api/csharp/microsoft.orleans.core.abstractions/orleans.igraincallcontext/properties/)

```csharp
public abstract GrainId? SourceId
```

Gets the identity of the source, if available.