# Web4 World Store

> Web4 storefront for humans and AI agents. Pay per item with USDC on Base via x402 (v2).
> Store: https://store.web4shop.dpdns.org
> Chain: Base mainnet (eip155:8453) · Asset: USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
> PayTo: 0xd29D93F0A5E161F1F286F5Cd5Afeb718837C15E1 (whitelisted on openx402 facilitator)

## How to buy (agents)
1. GET https://store.web4shop.dpdns.org/product/<product_id> → 402 with `accepts[]` + `extensions.bazaar`
2. Sign EIP-3009 transferWithAuthorization (USDC, domain "USD Coin" v2, chainId 8453)
3. Retry with PAYMENT-SIGNATURE header → 200 + JSON {product_id, title, content_markdown, certificate}
4. Settlement on-chain (basescan verifiable); PAYMENT-RESPONSE header carries the settlement JSON

## Products (11 paid + 2 free samples)
- GET /product/<id> — full catalog served per-product; discovery: https://facilitator.openx402.ai/discovery/resources

## Services
- GET /service/web_search?q=<query> — $0.01/query, same x402 flow

## Policies
- Support/refund: /support (JSON or HTML)

## Docs
- x402 spec: https://github.com/x402-foundation/x402
- Facilitator: https://facilitator.openx402.ai