Koto.Domain 0.1.0-preview.5

This is a prerelease version of Koto.Domain.

dotnet add package Koto.Domain --version 0.1.0-preview.5

NuGet\Install-Package Koto.Domain -Version 0.1.0-preview.5

This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.

<PackageReference Include="Koto.Domain" Version="0.1.0-preview.5" />

For projects that support PackageReference, copy this XML node into the project file to reference the package.

<PackageVersion Include="Koto.Domain" Version="0.1.0-preview.5" />
                    

                            Directory.Packages.props

<PackageReference Include="Koto.Domain" />
                    

                            Project file

For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package.

paket add Koto.Domain --version 0.1.0-preview.5

The NuGet Team does not provide support for this client. Please contact its maintainers for support.

#r "nuget: Koto.Domain, 0.1.0-preview.5"

#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.

#:package Koto.Domain@0.1.0-preview.5

#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package.

#addin nuget:?package=Koto.Domain&version=0.1.0-preview.5&prerelease
                    

                            Install as a Cake Addin

#tool nuget:?package=Koto.Domain&version=0.1.0-preview.5&prerelease
                    

                            Install as a Cake Tool

The NuGet Team does not provide support for this client. Please contact its maintainers for support.

Koto.Domain

DDD building blocks for .NET microservices. Zero external dependencies.

Install

dotnet add package Koto.Domain

What's included

Type	Purpose
`AggregateRoot<TId>`	Base class that collects domain events
`Entity<TId>`	Identity-based equality
`ValueObject`	Component-based equality
`StronglyTypedId<T>`	Typed wrappers for Guid / int / string IDs
`Result<T>`	Explicit success/failure without exceptions
`Error`	Structured error: `Code` + `Message`
`Errors.General`	Shared factory errors (not-found, required, …)
`IRepository<TAgg, TId>`	Persistence contract for aggregates
`IDomainEvent` / `DomainEvent`	Event interfaces and base record
`Unit`	Return type for commands that produce no value

Usage

Value Object

public sealed class Email : ValueObject
{
    public string Value { get; }
    private Email(string value) => Value = value;

    public static Result<Email> Create(string value) =>
        string.IsNullOrWhiteSpace(value) ? Errors.General.ValueIsRequired() :
        value.Length > 150              ? Errors.General.InvalidLength(1, 150) :
                                          new Email(value);

    protected override IEnumerable<object?> GetEqualityComponents()
    {
        yield return Value.ToLowerInvariant();
    }
}

Aggregate Root

public sealed record OrderId(Guid Value) : StronglyTypedId<Guid>(Value);

public class Order : AggregateRoot<OrderId>
{
    public static Result<Order> Place(IReadOnlyList<OrderItem> items)
    {
        if (items.Count == 0)
            return Errors.General.CollectionIsTooSmall(1, 0);

        var order = new Order(new OrderId(Guid.NewGuid()));
        order.AddDomainEvent(new OrderPlacedEvent(order.Id));
        return order;
    }

    public Result<Unit> Cancel(string reason)
    {
        if (Status == OrderStatus.Cancelled)
            return new Error("orders.already-cancelled", "Order is already cancelled.");

        Status = OrderStatus.Cancelled;
        AddDomainEvent(new OrderCancelledEvent(Id, reason));
        return Unit.Value;
    }
}

Result chaining

Result<OrderId> result = await ValidateAsync(request)
    .BindAsync(dto => Order.Place(dto.Items))
    .TapAsync(order => repository.Add(order))
    .MapAsync(order => order.Id);

Repository

public interface IOrderRepository : IRepository<Order, OrderId> { }

License

MIT

Product	Compatible and additional computed target framework versions.
.NET	net10.0 is compatible. net10.0-android was computed. net10.0-browser was computed. net10.0-ios was computed. net10.0-maccatalyst was computed. net10.0-macos was computed. net10.0-tvos was computed. net10.0-windows was computed.

Compatible target framework(s)

Included target framework(s) (in package)

Learn more about Target Frameworks and .NET Standard.

net10.0
- No dependencies.

NuGet packages (6)

Showing the top 5 NuGet packages that depend on Koto.Domain:

Package	Downloads
Koto.Application CQRS dispatcher, pipeline behaviors, and cross-service integration abstractions for .NET microservices. Depends only on Koto.Domain and Microsoft.Extensions abstractions.	160
Koto.Validation FluentValidation v7 extensions for Koto: MustBeValueObject, MustBeEntity, ListMustContainNumberOfItems, and ValidationBehavior pipeline integration.	143
Koto.EventSourcing.Marten Event Sourcing on PostgreSQL via Marten 8: EventSourcedAggregateRoot, event-sourced repository, inline and async projections.	100
Koto.Infrastructure.Http Anti-Corruption Layer for HTTP calls between services: typed ServiceHttpClient base, Result-mapped error handling, correlation ID propagation, and standard resilience.	95
Koto.Infrastructure.EFCore EF Core 10 integration for Koto DDD: generic repository, strongly-typed ID converters, specification pattern, and Wolverine outbox wiring.	94

GitHub repositories

This package is not used by any popular GitHub repositories.

Version	Downloads	Last Updated
0.1.0-preview.5	40	5/13/2026
0.1.0-preview.4	40	5/13/2026
0.1.0-preview.3	43	5/13/2026
0.1.0-preview.2	47	5/11/2026
0.1.0-preview.1	44	5/11/2026