ASP.NET Core and OpenAPI

Install the integrations you use:

dotnet add package Valiant.Validation.AspNetCore
dotnet add package Valiant.Validation.AspNetCore.OpenApi

Minimal APIs

Register validators and attach validation to a route:

builder.Services.AddValiantValidators();

app.MapPost("/users", (CreateUser request) => Results.Created())
    .WithValiantValidation();

The non-generic overload validates every eligible handler argument with a registered validator. Use the typed overload to select one request type explicitly:

app.MapPost("/users", (CreateUser request, CancellationToken cancellationToken) =>
        Results.Created())
    .WithValiantValidation<CreateUser>();

Failures return HTTP validation problem details before the handler runs.

MVC

Register the global model-validation filter directly or through MVC builders:

builder.Services.AddValiantValidators();
builder.Services.AddValiantMvcValidation();

// Equivalent integration point:
builder.Services.AddControllers().AddValiantValidation();

Problem details helpers

Use ValiantProblemDetails when your endpoint or controller validates manually:

var result = await validator.ValidateAsync(request, cancellationToken);
if (!result.IsValid)
{
    return Results.ValidationProblem(result.ToValidationProblemDictionary());
}

Helpers are available for Minimal API HttpValidationProblemDetails, MVC ValidationProblemDetails, and property-to-message dictionaries.

OpenAPI

builder.Services.AddOpenApi();
builder.Services.AddValiantOpenApi();

Or attach the transformer to a specific OpenAPI document:

builder.Services.AddOpenApi(options =>
    options.AddValiantValidationRules());

Valiant projects generated metadata into native constraints where possible—such as required, length, count, and comparison bounds—and preserves richer details in x-valiant-rules extensions.

Package references

Each integration package forwards the core Valiant runtime and generator assets. Add both ASP.NET Core packages when you need request validation and OpenAPI; do not add a redundant direct Valiant.Validation reference.

The Validation sample catalog links the Minimal API, MVC, problem-details, and OpenAPI startup implementations.