Crate domainstack 

domainstack

domainstack turns untrusted input into valid-by-construction domain objects, and returns stable, field-level errors your APIs and UIs can depend on.

It’s built for the boundary you actually live at:

HTTP/JSON/etc. → DTOs → Domain (validated) → Business logic

Most validation crates ask: “Is this DTO valid?” domainstack asks: “How do I safely construct domain models from untrusted input—and report failures with a consistent error contract?”

What that gives you

• Domain-first modeling: invalid states are hard/impossible to represent
• Composable rule algebra: reusable rules with .and(), .or(), .when()
• Structured error paths: rooms[0].adults, guest.email.value (UI-friendly)
• Async validation with context: DB/API checks like uniqueness, rate limits
• Cross-field validation: invariants like password confirmation, date ranges
• Type-state tracking: phantom types to enforce “validated” at compile time
• Schema + client parity: generate OpenAPI and TypeScript/Zod from the same Rust rules
• Framework adapters: one-line boundary extraction (Axum / Actix / Rocket)
• Lean core: zero-deps base, opt-in features for regex / async / chrono / serde

Quick Start

use domainstack::prelude::*;

// Validate a username with composable rules
let username = "alice";
let rule = rules::min_len(3).and(rules::max_len(20));

match validate("username", username, &rule) {
    Ok(_) => println!("Username is valid!"),
    Err(e) => {
        for v in &e.violations {
            println!("[{}] {} - {}", v.path, v.code, v.message);
        }
    }
}

For more complex examples with #[derive(Validate)], cross-field validation, and nested types, see the examples directory or check out the booking system example in the README.

With framework adapters (Axum/Actix/Rocket), this becomes a one-line extraction: DomainJson<Booking, BookingDto> automatically deserializes, validates, and converts DTOs to domain types—returning structured errors to clients on failure.

Documentation

• Core Concepts - Foundation principles and patterns
• Rules Reference - All 37 validation rules
• Examples - 9 runnable examples

Modules

prelude

rules

typestate

Type-state validation markers for compile-time validation guarantees.

Structs

Meta

Path

Represents a path to a field in a nested structure.

Rule

A composable validation rule for values of type T.

RuleContext

Context information available to validation rules.

ValidationError

Represents a collection of validation violations.

Violation

Enums

PathSegment

Traits

Validate

Functions

validate