Introduction

zigantic is a Pydantic-like data validation library for Zig. It brings the power of type-safe validation to Zig, using the type system for compile-time guarantees.

What is zigantic?

zigantic allows you to:

• Define validation rules as types - Instead of runtime checks, validation constraints are expressed as types
• Parse JSON with automatic validation - Convert JSON to validated Zig structs in one step
• Serialize validated data - Convert structs back to JSON easily
• Get human-readable errors - Field-aware error messages with error codes

Why zigantic?

Compile-Time Guarantees

Validation rules are expressed as types, so invalid constraints fail at compile time:

// This won't compile - min > max
const Invalid = z.String(100, 10); // Compile error!

Self-Documenting Code

Types describe their own constraints:

const User = struct {
    name: z.String(1, 50),      // 1-50 characters
    age: z.Int(i32, 18, 120),   // 18-120
    email: z.Email,             // Valid email format
};

Zero Runtime Overhead

Unused features have no cost. If you don't use JSON parsing, it's not compiled in.

IDE Support

Full type information everywhere - autocomplete, hover documentation, and refactoring support.

Quick Example

const std = @import("std");
const z = @import("zigantic");

pub fn main() !void {
    // Direct validation
    const email = try z.Email.init("user@example.com");
    std.debug.print("Domain: {s}\n", .{email.domain()});

    // JSON parsing
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    const User = struct {
        name: z.String(1, 50),
        age: z.Int(i32, 0, 150),
    };

    const json = 
        \\{"name": "Alice", "age": 25}
    ;

    var result = try z.fromJson(User, json, allocator);
    defer result.deinit();

    if (result.value) |user| {
        std.debug.print("User: {s}, Age: {d}\n", .{user.name.get(), user.age.get()});
    }
}

Key Features

Feature	Description
50+ Built-in Types	Strings, numbers, emails, URLs, UUIDs, dates, coordinates, and more
JSON Serialization	Parse and serialize JSON with automatic validation
Custom Validators	Define your own validation logic with Custom type
Transformations	Transform values during validation with Transform type
Default Values	Specify defaults with Default type
Partial Types	Make all fields optional with Partial
Human-Readable Errors	Field-aware messages with error codes

Type Categories

String Types

String, NonEmptyString, Trimmed, Lowercase, Uppercase, Alphanumeric, AsciiString, Secret, StrongPassword

Number Types

Int, UInt, PositiveInt, NonNegativeInt, NegativeInt, EvenInt, OddInt, MultipleOf, Float, Percentage, Probability, PositiveFloat, NegativeFloat, FiniteFloat

Format Types

Email, Url, HttpsUrl, Uuid, Ipv4, Ipv6, Slug, Semver, PhoneNumber, CreditCard, Regex, Base64, HexString, HexColor, MacAddress, IsoDateTime, IsoDate, CountryCode, CurrencyCode, Latitude, Longitude, Port

Collection Types

List, NonEmptyList, FixedList

Special Types

Default, Custom, Transform, Coerce, Literal, Partial, OneOf, Range, Nullable, Lazy

Next Steps

• Installation - Install zigantic in your project
• Getting Started - Create your first validation
• Types API - Full reference for all types
• JSON API - JSON serialization and deserialization