stateset-core

Pure domain models and business logic for commerce applications. No I/O, no runtime — just the type system, validation, events, and repository traits you need to build a commerce backend.

Because there's no I/O in here, the domain is testable without a database and portable to any storage you like: implement the repository traits and the models, state machines, and validation come along unchanged.

Part of the StateSet iCommerce engine.

What's Inside

• 35+ domain modules: orders, payments, inventory, customers, products, carts, returns, subscriptions, shipments, manufacturing, promotions, tax, analytics, and more
• State machines: OrderStatus, PaymentTransactionStatus, SubscriptionStatus with exhaustive match enforcement
• Event sourcing: CommerceEvent with 30+ variants for full audit trails
• Validation framework: composable ValidationBuilder with validators for email, SKU, phone, postal code, price, quantity
• Repository traits: generic Repository, auto-implemented for &T, Box<T>, Arc<T>
• Error taxonomy: CommerceError with is_not_found(), is_retryable(), suggested_status_code(), and domain-specific sub-errors
• Agent-to-agent commerce: A2A quotes, purchases, subscriptions, split payments, escrow
• Crypto primitives: x402 payment intents, ERC-8004 identity, Merkle proofs

Usage

Errors are categorized, so callers branch on meaning rather than on strings:

use stateset_core::CommerceError;

fn handle_error(err: &CommerceError) {
    if err.is_not_found() {
        // 404
    } else if err.is_validation() {
        // 400
    } else if err.is_conflict() {
        // 409
    } else if err.is_retryable() {
        // back off and retry
    }
}

Validation composes and returns a single Result carrying every failure:

use stateset_core::{ValidationBuilder, Result};

fn validate_order(email: &str, quantity: i32) -> Result<()> {
    ValidationBuilder::new()
        .email("email", email)
        .positive_i32("quantity", quantity)
        .build()
}

assert!(validate_order("alice@example.com", 2).is_ok());
assert!(validate_order("not-an-email", 2).is_err());
assert!(validate_order("alice@example.com", -1).is_err());

Feature Flags

Part of StateSet iCommerce

Built on stateset-primitives and implemented against by stateset-db. Most applications consume it via stateset-embedded or stateset-sdk.

License

MIT OR Apache-2.0