llms.txt

# x402-fetch

> Drop-in fetch wrapper that auto-pays HTTP 402 endpoints on Abstract chain via the x402 protocol. Wraps native fetch(), signs ERC-3009 transferWithAuthorization with a viem wallet client, retries with the X-PAYMENT header.

## Usage

Install: `npm install x402-fetch viem`

```typescript
import { createX402Fetch } from "x402-fetch";
const x402fetch = createX402Fetch(walletClient);
const res = await x402fetch("https://api.example.com/paid-endpoint");
```

## How it works

1. Call x402fetch() like normal fetch()
2. Non-402 responses pass through unchanged
3. On 402, parses payment requirements from response body
4. Signs ERC-3009 transferWithAuthorization via viem wallet
5. Retries with signed payment as base64 JSON in X-PAYMENT header

## Programmatic API

```typescript
import { createX402Fetch } from "x402-fetch";

const x402fetch = createX402Fetch(walletClient, {
  maxPayment: "0.01",
  onPayment: (details) => console.log(details),
});
```

## Related

- [viem](https://viem.sh): TypeScript interface for Ethereum