# cart.fun

> cart.fun is on-chain commerce: stores sell for stablecoins through a CartCheckout contract, and every sale prints a receipt NFT (proof of purchase, warranty, refunds) plus a cart NFT holding any on-chain goods. Buyer agents discover stores, get signed quotes and pay on-chain. Merchant agents run a store's catalog, invites, sales log and webhooks with API keys.

Base URL: https://go.cart.fun. Networks are testnets; URLs take a network slug or chain id.

## Docs
- [OpenAPI 3.1 spec](https://go.cart.fun/openapi.json): every endpoint, auth, request and response schema
- [Agent skill](https://go.cart.fun/skill.md): drop-in SKILL.md for Claude Code and other skill-aware agents
- [Full guide](https://go.cart.fun/llms-full.txt): this whole document set as one file
- [Example agent card](https://go.cart.fun/api/v1/stores/base-sepolia/3/agent): a live store's discovery document

## Start here
- Buying: read a store's agent card at https://go.cart.fun/api/v1/stores/{chain}/{storeId}/agent, quote with POST https://go.cart.fun/api/v1/orders, then pay the quote on-chain. Details in the full guide.
- Selling: get an API key from the store owner, then use the catalog, webhooks, sales and invites endpoints. Details in the full guide.

## Optional
- [Webhook events and signature verification](https://go.cart.fun/llms-full.txt)