Is there a library that contains ProblemDetails, without adding ASP.NET SDK?

[paulomorgado]

What if I need it for non-web scenarios, like mobile applications or WebAssembly?

[mr-baraiya]

Yes. You can use the Microsoft.AspNetCore.Mvc.Abstractions or Microsoft.AspNetCore.Mvc.Core packages, which contain the ProblemDetails class without requiring the full ASP.NET Core web stack.

If you only need the data structure for error responses (for example in mobile apps, WebAssembly, or shared libraries), referencing Microsoft.AspNetCore.Mvc.Core is usually sufficient.

Another option is to implement your own lightweight ProblemDetails class following the RFC 7807 specification if you want to avoid ASP.NET dependencies entirely.

[paulomorgado]

Microsoft.AspNetCore.Mvc.Core does have a Microsoft.AspNetCore.Mvc.ProblemDetails and a Microsoft.AspNetCore.Mvc.ValidationProblemDetails, that are not Microsoft.AspNetCore.Mvc.ProblemDetails and Microsoft.AspNetCore.Mvc.ValidationProblemDetails and does not have a HttpValidationProblemDetails.

Microsoft.AspNetCore.Mvc.Core also comes with an acceptable amount of dependencies to client code.

[mr-baraiya]

You're right that Microsoft.AspNetCore.Mvc.Core brings additional dependencies and doesn't include HttpValidationProblemDetails.
If you specifically need HttpValidationProblemDetails, it is available in the Microsoft.AspNetCore.Http package starting from .NET 7+, which has fewer MVC dependencies.

Otherwise, for non-web scenarios where minimizing dependencies is important, implementing a small RFC 7807–compliant ProblemDetails class might be the most lightweight option.

[paulomorgado]

Do you mean Microsoft.AspNetCore.Http?

Doesn't seem to have it:

PS> dnx dotnet-inspect type --package Microsoft.AspNetCore.Http
Tool package dotnet-inspect@0.6.9 will be downloaded from source https://api.nuget.org/v3/index.json.
Proceed? [y/n] (y): y
KIND    TYPE                                                                         MEMBERS
class   Microsoft.AspNetCore.Builder.Internal.ApplicationBuilder                     8
class   Microsoft.AspNetCore.Http.DefaultHttpContext                                 16
class   Microsoft.AspNetCore.Http.Features.Authentication.HttpAuthenticationFeature  3
class   Microsoft.AspNetCore.Http.Features.DefaultSessionFeature                     2
class   Microsoft.AspNetCore.Http.Features.FormFeature                               8
class   Microsoft.AspNetCore.Http.Features.FormOptions                               15
class   Microsoft.AspNetCore.Http.Features.HttpConnectionFeature                     6
class   Microsoft.AspNetCore.Http.Features.HttpRequestFeature                        10
class   Microsoft.AspNetCore.Http.Features.HttpRequestIdentifierFeature              2
class   Microsoft.AspNetCore.Http.Features.HttpRequestLifetimeFeature                3
class   Microsoft.AspNetCore.Http.Features.HttpResponseFeature                       8
class   Microsoft.AspNetCore.Http.Features.ItemsFeature                              2
class   Microsoft.AspNetCore.Http.Features.QueryFeature                              3
class   Microsoft.AspNetCore.Http.Features.RequestCookiesFeature                     3
class   Microsoft.AspNetCore.Http.Features.ResponseCookiesFeature                    3
class   Microsoft.AspNetCore.Http.Features.ServiceProvidersFeature                   2
class   Microsoft.AspNetCore.Http.Features.TlsConnectionFeature                      3
class   Microsoft.AspNetCore.Http.FormCollection                                     9
class   Microsoft.AspNetCore.Http.HeaderDictionary                                   19
class   Microsoft.AspNetCore.Http.HttpContextAccessor                                2
class   Microsoft.AspNetCore.Http.HttpContextFactory                                 4
class   Microsoft.AspNetCore.Http.HttpRequestRewindExtensions                        4
class   Microsoft.AspNetCore.Http.Internal.BindingAddress                            11
class   Microsoft.AspNetCore.Http.Internal.BufferingHelper                           3
class   Microsoft.AspNetCore.Http.Internal.DefaultConnectionInfo                     10
class   Microsoft.AspNetCore.Http.Internal.DefaultHttpRequest                        21
class   Microsoft.AspNetCore.Http.Internal.DefaultHttpResponse                       14
class   Microsoft.AspNetCore.Http.Internal.DefaultWebSocketManager                   6
class   Microsoft.AspNetCore.Http.Internal.FormFile                                  10
class   Microsoft.AspNetCore.Http.Internal.FormFileCollection                        4
class   Microsoft.AspNetCore.Http.Internal.ItemsDictionary                           3
class   Microsoft.AspNetCore.Http.Internal.QueryCollection                           11
class   Microsoft.AspNetCore.Http.Internal.RequestCookieCollection                   11
class   Microsoft.AspNetCore.Http.Internal.ResponseCookies                           5
class   Microsoft.AspNetCore.Http.MiddlewareFactory                                  3
class   Microsoft.AspNetCore.Http.RequestFormReaderExtensions                        1
class   Microsoft.Extensions.DependencyInjection.HttpServiceCollectionExtensions     1
struct  Enumerator                                                                   3
struct  Enumerator                                                                   3
struct  Enumerator                                                                   3
struct  Enumerator                                                                   4

[mr-baraiya]

You're right — thanks for checking.

HttpValidationProblemDetails is not in Microsoft.AspNetCore.Http. It is defined in the Microsoft.AspNetCore.Http.Abstractions assembly and exposed through the Microsoft.AspNetCore.Http shared framework starting with .NET 7+, but it isn’t available as a standalone minimal dependency via the Microsoft.AspNetCore.Http NuGet package.

So if the goal is to avoid pulling the ASP.NET Core shared framework or MVC dependencies, the practical options are:

1. Reference Microsoft.AspNetCore.Mvc.Core (which includes ProblemDetails and ValidationProblemDetails) and accept the additional dependencies, or
2. Implement a small RFC 7807–compliant ProblemDetails type in your own code for non-web/client scenarios.

For client/mobile/WASM libraries where dependency size matters, the second approach is often the most lightweight.