# x402-feed

> Agent-payable, real-time collectibles price feed. Pay-per-call over HTTP using the
> x402 "Payment Required" protocol (Coinbase standard, USDC on Base). No signup, no
> API key, no rate limits beyond payment. Built for autonomous AI agents.

## How to consume (for an AI agent)

1. GET https://x402.dropwatchhq.com/api/check?niche=funko&q=batman
   -> HTTP 402 with JSON body:
      { "x402Version": 1, "accepts": [ { "scheme": "exact", "network": "base",
        "maxAmountRequired": "10000", "asset": "<USDC on Base>", "payTo": "<wallet>",
        "resource": "...", "maxTimeoutSeconds": 60, "extra": {"name":"USDC","version":"2"} } ] }

2. Construct an EIP-3009 transferWithAuthorization for 10000 atomic USDC units
   ($0.01) to payTo, sign it (EIP-712), and base64-encode the
   PaymentPayload: { "x402Version":1, "scheme":"exact", "network":"base",
   "payload": { "signature":"0x...", "authorization": { from, to, value, validAfter, validBefore, nonce } } }

3. Retry the SAME GET with header  X-PAYMENT: <base64 payload>
   -> HTTP 200 with the data, plus X-PAYMENT-RESPONSE header (base64 settlement receipt).

Use the official x402 client SDKs (x402-fetch / x402-axios) and they will do steps 1-3 for you.

## Price

- 10000 atomic units = $0.01 USDC per successful call.
- Network: base (Base mainnet). Asset: USDC (6 decimals).

## Endpoints

- GET /api/check?niche=<funko|tcg|lego|keebs|vinyl|aqua>&q=<product>   (402-gated)
- GET /health    -> liveness JSON
- GET /llms.txt  -> this file
- GET /.well-known/x402 -> machine-readable service + price descriptor

## Spec

Implements x402 v1 (scheme "exact", EVM EIP-3009). See https://github.com/coinbase/x402
and https://docs.x402.org . Facilitator: https://facilitator.payai.network .