Fetch Sentry Buyer Quickstart

Install buyer packages:
npm install @x402/fetch @x402/evm @x402/core viem

Prepare payment wallet:
- fund an EVM wallet with Base USDC
- set EVM_PRIVATE_KEY in your environment

Example paid endpoint:
https://api.fetch-sentry.online/fetch?url=https%3A%2F%2Fexample.com

Run flow:
1. create a signer from EVM_PRIVATE_KEY
2. register ExactEvmScheme for eip155:*
3. wrap fetch with wrapFetchWithPayment(fetch, client)
4. call the paid URL
5. read the JSON response
6. inspect PAYMENT-RESPONSE if you want settlement metadata

Full example source: https://api.fetch-sentry.online/buyer-example.ts
Official docs:
- https://docs.x402.org/getting-started/quickstart-for-buyers

Expected result:
- first request receives HTTP 402 and auto-pays
- second leg settles payment and returns 200