Kopticx.Validify

Validify is a lightweight validation filter for ASP.NET Core Minimal APIs powered by FluentValidation. It wires model validation into your endpoint pipeline with one line per endpoint — and a source generator registers all your validators for you, with zero runtime reflection so the whole thing stays fully Native AOT compatible.

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✨ Features

• ✅ Declarative model validation for Minimal APIs via .WithValidation<T>()
• 🔄 Built on FluentValidation — full rule set: conditional, cross-property, async, custom messages
• 🤖 Source-generated auto-registration — one AddValidifyValidators() call registers every validator; no manual AddSingleton per model
• 📦 Per-project registration — auto-registers the validators of the project it's installed in; register cross-assembly validators manually with AddSingleton
• ⚙️ 100% Native AOT compatible — discovery happens at compile time, no runtime reflection
• 🛡️ Stops invalid requests before they reach your handlers, with an RFC 9457 HttpValidationProblemDetails
• 🧩 Plug-and-play with Microsoft.Extensions.DependencyInjection

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🚀 Installation

dotnet add package Kopticx.Validify

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🛠️ Setup

1. Register Validify

builder.Services.AddValidify();// the validation filterbuilder.Services.AddValidifyValidators();// source-generated — registers all your validators

2. Write FluentValidation validators

publicsealedclassPostUserModelValidator:AbstractValidator<PostUserModel>{publicPostUserModelValidator(){RuleFor(x =>x.Username).NotEmpty().WithMessage("Username is required").MaximumLength(255).WithMessage("Must be less than 255 characters");}}

3. Apply validation to an endpoint

app.MapPost("/users",PostUser).WithValidation<PostUserModel>();

If the model is invalid, the filter short-circuits with a 400 Bad Request carrying an HttpValidationProblemDetails (RFC 9457) — your handler never runs.

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🤖 Auto-registration (source generator)

AddValidifyValidators() is generated at compile time into your startup assembly. It discovers every AbstractValidator<T> and registers IValidator<T> → your concrete validator — no reflection, no per-model boilerplate.

It registers with TryAdd, so it coexists with manual registration: anything you register by hand takes precedence, and the generator fills in the rest.

// Still valid — a manual registration wins over the generated one:services.AddSingleton<IValidator<PostUserModel>,PostUserModelValidator>();

Discovery is per-project: the generator registers validators declared in the project where the package is installed. To register a validator that lives in another assembly, register it by hand (it coexists with the generated registrations):

services.AddSingleton<IValidator<SomeModel>,SomeValidator>();

The default lifetime is Scoped (matching FluentValidation's own default); override it if needed:

builder.Services.AddValidifyValidators(ServiceLifetime.Singleton);

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⚙️ Native AOT

Validify is 100% AOT-compatible: discovery and registration are resolved at compile time with no runtime reflection. Publish your API as a native executable:

<PublishAot>true</PublishAot>

So the 400 response can be serialized under source-generated System.Text.Json, add HttpValidationProblemDetails to your JsonSerializerContext:

[JsonSerializable(typeof(HttpValidationProblemDetails))]publicpartialclassAppJsonContext:JsonSerializerContext;

The repo's samples/Validify.AotSample is a Minimal API published with PublishAot that registers its validators through the generator — proving the AOT path end to end.

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🤔 Validify vs .NET 10 native validation

.NET 10 introduced built-in Minimal API validation (AddValidation() plus a source generator over DataAnnotations attributes) — a great fit when DataAnnotations covers your needs. Validify is for teams who prefer FluentValidation:

	Validify	.NET 10 native validation
Validation engine	FluentValidation	DataAnnotations
Where rules live	Dedicated validator classes, decoupled from the model	Attributes on the model
Expressiveness	Fluent API: conditional, cross-property, async, custom messages	Attribute set; custom via IValidatableObject / custom attributes
Validator testability	Plain classes, unit-testable in isolation	Coupled to the model
Registration	One source-generated AddValidifyValidators() (or manual)	AddValidation() + source-gen over annotated types
Discovery scope	The installing project's validators (cross-assembly is manual)	Per annotated type
Native AOT	✅	✅
Minimum target	.NET 8	.NET 10

Both are source-generated and AOT-friendly — the real decision is FluentValidation vs DataAnnotations.

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📝 License

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📄 Third-party licenses

Validify uses FluentValidation, licensed under the Apache 2.0 License.

See NOTICE file for more information.