# FastBuy AI

> AI-powered shopping assistant for Shopify stores. Search products by keyword, get images/prices/sizes, and create checkout links. No authentication required.

FastBuy AI lets AI assistants search products across multiple stores and generate direct checkout links. The user never needs to install anything or authenticate. All browsing happens in the chat; the user only leaves to complete payment. Search is powered by both our custom AAIP backend and Shopify's native Storefront MCP servers for maximum reliability.

## API Endpoints

- [Search products JSON](https://fastbuyai.com/shop?q=QUERY): GET /shop?q={query} returns JSON with products, images, prices, variants, sizes/colors
- [Create checkout](https://fastbuyai.com/buy?store=STORE&variant=VARIANT_ID): GET /buy returns checkout URL for a specific variant
- [AI instructions](https://fastbuyai.com/ai): Step-by-step guide for AI assistants
- [Search HTML](https://fastbuyai.com/s/QUERY): GET /s/{query} returns HTML product gallery with Schema.org markup

## MCP Server

- [MCP endpoint](https://fastbuyai.com/mcp): Streamable HTTP transport, no authentication
- [MCP discovery](https://fastbuyai.com/.well-known/mcp.json): Server capabilities and tools

## Shopify Storefront MCP (Supplemental)

Each connected Shopify store also exposes Shopify's native Storefront MCP server at https://{store}.myshopify.com/api/mcp. FastBuy AI queries these in parallel with our AAIP backend for broader product coverage and checkout fallback. Storefront MCP tools: search_shop_catalog, search_shop_policies_and_faqs, get_cart, update_cart.

## Discovery

- [ChatGPT plugin](https://fastbuyai.com/.well-known/ai-plugin.json): OpenAI plugin manifest (authless)
- [Agent card](https://fastbuyai.com/.well-known/agent.json): A2A agent discovery
- [OpenAPI spec](https://fastbuyai.com/openapi-chatgpt.json): OpenAPI 3.1 specification
- [Privacy policy](https://fastbuyai.com/privacy): Data handling and privacy

## Google UCP (Universal Commerce Protocol)

- [UCP business profile](https://fastbuyai.com/.well-known/ucp): Discovery for Google AI Mode and Gemini
- [UCP checkout API](https://fastbuyai.com/ucp/checkout-sessions): Native checkout sessions (REST)
- POST /ucp/checkout-sessions — Create session with line items
- GET /ucp/checkout-sessions/{id} — Get session state
- PUT /ucp/checkout-sessions/{id} — Update session (shipping, payment)
- POST /ucp/checkout-sessions/{id}/complete — Complete order
- POST /ucp/checkout-sessions/{id}/cancel — Cancel session

## Example Flow

1. User says "find me a t-shirt on fastbuyai.com"
2. AI fetches https://fastbuyai.com/shop?q=t-shirt
3. AI presents products with images, prices, and available sizes
4. User picks a product and size
5. AI fetches https://fastbuyai.com/buy?store=STORE&variant=VARIANT_ID
6. AI gives checkout link to user