ZeroAlloc.Validation 2.1.0

ZeroAlloc.Validation

Source-generated, attribute-based validation for .NET that allocates nothing on the valid path. The source generator emits a strongly-typed validator class at build time — no reflection at runtime. When all rules pass, the entire validation cycle produces zero heap allocations.

Install

dotnet add package ZeroAlloc.Validation

ZeroAlloc.Validation bundles its own source generator — no other package is required.

Upgrading from an older version? If your project also references ZeroAlloc.Validation.Generator directly, remove that PackageReference — the generator now ships inside ZeroAlloc.Validation itself, and keeping both loads it twice, which fails the build with ZV9001.

30-Second Example

using ZeroAlloc.Validation;

[Validate]
public class CreateOrderRequest
{
    [NotEmpty][MaxLength(50)] public string  Reference { get; set; } = "";
    [GreaterThan(0)]          public decimal Amount    { get; set; }
    [NotEmpty][EmailAddress]  public string  Email     { get; set; } = "";
}

// The source generator emits CreateOrderRequestValidator at build time
var request   = new CreateOrderRequest
{
    Reference = "ORD-2026-001",
    Amount    = 99.99m,
    Email     = "customer@example.com"
};
var validator = new CreateOrderRequestValidator();
var result    = validator.Validate(request);

if (!result.IsValid)
    foreach (ref readonly var f in result.Failures)
        Console.WriteLine($"{f.PropertyName}: {f.ErrorMessage}");

Performance

See Performance for full benchmark results.

Packages

Features

• Zero heap allocation on the valid path
• 25+ built-in validation attributes
• Nested object and collection validation
• Inherited rules from base types (opt out with [Validate(IncludeBaseProperties = false)])
• ASP.NET Core auto-validation (HTTP 422 on failure)
• Zero-friction DI registration (AddZeroAllocValidators())
• Source-generated Microsoft.Extensions.Options integration (ValidateWithZeroAlloc())
• Per-rule severity (Error, Warning, Info)
• Conditional rules (When / Unless / [SkipWhen])
• Short-circuit with [StopOnFirstFailure]
• Custom rules via reusable ValidationAttribute<T> attributes, [Must] predicates or [CustomValidation] methods
• Asynchronous rules via AsyncValidationAttribute<T>, awaited by the generated ValidateAsync
• Testing helpers via ZeroAlloc.Validation.Testing

Documentation

• Getting Started
• Attribute Reference
• Nested Validation
• Collection Validation
• Custom Validation
• Error Messages
• ASP.NET Core Integration
• DI Registration (Inject)
• Options Validation
• Testing
• Performance
• Advanced Features
• Migrating to v2