ErrorApi.LanguageExt.V5
1.0.1-beta.1
dotnet add package ErrorApi.LanguageExt.V5 --version 1.0.1-beta.1
NuGet\Install-Package ErrorApi.LanguageExt.V5 -Version 1.0.1-beta.1
<PackageReference Include="ErrorApi.LanguageExt.V5" Version="1.0.1-beta.1" />
<PackageVersion Include="ErrorApi.LanguageExt.V5" Version="1.0.1-beta.1" />
<PackageReference Include="ErrorApi.LanguageExt.V5" />
paket add ErrorApi.LanguageExt.V5 --version 1.0.1-beta.1
#r "nuget: ErrorApi.LanguageExt.V5, 1.0.1-beta.1"
#:package ErrorApi.LanguageExt.V5@1.0.1-beta.1
#addin nuget:?package=ErrorApi.LanguageExt.V5&version=1.0.1-beta.1&prerelease
#tool nuget:?package=ErrorApi.LanguageExt.V5&version=1.0.1-beta.1&prerelease

ErrorApi.LanguageExt.V5
The language-ext v5 twin of ErrorApi.LanguageExt: the
same surface — Fin<T>.ToHttpResult(), ToCreated, ToCreatedAtRoute, Either<Error, T> — compiled
against the 5.x API, so every endpoint's OpenAPI document lists the failures it can actually return and
the wire response carries a stable machine-readable code.
dotnet add package ErrorApi.LanguageExt.V5 --prerelease
Prerelease, on purpose. language-ext 5.0.0 has no stable release yet, and NuGet rightly refuses a stable package with a prerelease dependency. This package tracks the beta and goes stable the moment 5.0.0 does. On v4? Use
ErrorApi.LanguageExt— the two packages are alternatives, never references of one project.
Usage
Identical to the v4 adapter — annotate your own Expected subclasses, which is the idiomatic way to
model a domain failure in language-ext:
[ErrorApi.Error("Orders.NotFound", 404, Title = "Order not found")]
public sealed record OrderNotFound(Guid Id) : Expected("Order not found", 404);
public Fin<Order> GetById(Guid id) =>
_orders.TryGetValue(id, out var order) ? order : new OrderNotFound(id);
builder.Services.AddErrorApi();
orders.MapGet("/{id:guid}", (Guid id, IOrderService s) => s.GetById(id).ToHttpResult());
// Document: 200 + 404 with code "Orders.NotFound"; wire: the same problem body.
Resolution goes by type first, through the generated pattern switch. Failing that the numeric code is used when it already looks like an HTTP status; everything else becomes a 500.
Versions
Pinned to LanguageExt.Core 5.0.0-beta-77; the suite tracks newer betas via
-p:LanguageExtV5TestVersion=5.0.0-beta-xx.
| Product | Versions 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. |
-
net10.0
- ErrorApi.AspNetCore (>= 1.0.1)
- LanguageExt.Core (>= 5.0.0-beta-77)
- Microsoft.AspNetCore.OpenApi (>= 10.0.11)
NuGet packages
This package is not used by any NuGet packages.
GitHub repositories
This package is not used by any popular GitHub repositories.
| Version | Downloads | Last Updated |
|---|---|---|
| 1.0.1-beta.1 | 66 | 8/31/2026 |
| 1.0.0-beta.1 | 56 | 8/30/2026 |