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ASP.NET Core and OpenAPI

Install the integrations you use:

dotnet add package StaticNorth.Valiant.Validation.AspNetCore
dotnet add package StaticNorth.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 uses each non-null argument's exact declared parameter type. [ValiantValidator] discovery emits the validator, its typed invocation bridge, and their registrations into the generated AddValiantValidators() method. The normal path therefore needs no per-model registration or runtime assembly scan. The generated method covers default validators discovered in the current compilation. Arguments with the same declared type reuse the validators resolved for that request while retaining handler-argument execution order.

Use the typed overload to resolve IValidator<T> and validate every non-null handler argument assignable to T:

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

The generated parameterless path supports Native AOT. Manually registered raw IValidator<T> services without a generated bridge remain compatible through a JIT-only fallback. For an explicit manual registration in Native AOT, use the typed overload. MVC does not receive this Native AOT guarantee.

Errors return HTTP validation problem details before the handler runs. Warnings and informational failures do not block the handler.

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 StaticNorth.Valiant.Validation reference.

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