x402get

A CLI tool for HTTP GET requests with automatic x402 payment support. When a server responds with HTTP 402 Payment Required, x402get displays the price, checks your wallet balance, asks for confirmation, signs an EIP-3009 TransferWithAuthorization, and retries the request with payment.

Installation

# Run directly with npx
npx x402get https://google.com

# Or install globally
npm install -g x402get

Build from source

git clone https://github.com/anders94/x402get.git
cd x402get
npm install
npm run build
node dist/cli.js x402get

Requires Node.js 20+ (for native fetch).

Usage

x402get url [options]

Options

| Option | Description | |---|---| | -k, --private-key <key> | Private key for signing payments | | -r, --rpc <url> | RPC endpoint URL | | -o, --output <file> | Save response body to a file | | -h, --help | Show help |

Environment variables

| Variable | Description | |---|---| | PRIVATE_KEY | Default private key (overridden by --private-key) | | RPC_ENDPOINT | Default RPC URL (overridden by --rpc) |

Examples

Simple GET (no payment required)

x402get https://httpbin.org/get

Fetch a paid resource

export PRIVATE_KEY=0xabc123...
x402get https://api.example.com/paid-endpoint

Output:

Fetching https://api.example.com/paid-endpoint...

=== x402 Payment Required ===
Resource:    https://api.example.com/paid-endpoint
Description: Premium API access
Price:       0.01 USDC
Network:     Base
Pay to:      0x1234...abcd
Wallet:      0xabcd...1234
Balance:     5.00 USDC

Proceed with payment? [y/N] y
Signing payment...
Retrying request with payment...
Payment tx: 0xdeadbeef...
{"data": "the paid content"}
Done.

Pipe content to a file

All informational output goes to stderr, so stdout is clean for piping:

x402get https://api.example.com/paid-data > data.json

Save binary content

x402get https://api.example.com/paid-image -o image.png

Use a custom RPC

x402get https://api.example.com/resource --rpc https://my-rpc.example.com

How it works

1. GET request — x402get fetches the URL normally.
2. 200 OK — The response body is printed to stdout (text) or saved to a file (binary).
3. 402 Payment Required — The server includes a base64-encoded PAYMENT-REQUIRED header describing accepted payment methods.
4. Challenge parsing — x402get decodes the challenge and selects a compatible eip3009 (EIP-3009 TransferWithAuthorization) payment option.
5. Balance check — The tool queries the ERC-20 token contract for your wallet's balance.
6. Confirmation — A summary is displayed and you are prompted to approve or cancel.
7. EIP-712 signing — x402get signs a TransferWithAuthorization message using EIP-712 typed data. No on-chain transaction is sent by the client — the server submits it.
8. Retry — The original request is retried with a Payment-Signature header containing the signed authorization.
9. Response — The paid content is returned. If the server includes a PAYMENT-RESPONSE header with a transaction hash, it is displayed on stderr.

Supported chains

x402get includes built-in RPC endpoints and USDC token addresses for these networks:

| Chain | Chain ID | Default RPC | |---|---|---| | Ethereum | 1 | https://eth.llamarpc.com | | Base | 8453 | https://mainnet.base.org | | Base Sepolia | 84532 | https://sepolia.base.org | | Radius | 723 | https://rpc.radiustech.xyz | | Radius Testnet | 72344 | https://rpc-testnet.radiustech.xyz | | Polygon | 137 | https://polygon-rpc.com |

Any EVM chain using the CAIP-2 eip155:<chainId> format is supported — provide the RPC endpoint via --rpc or RPC_ENDPOINT for chains not listed above.

x402 protocol

The x402 protocol enables machine-to-machine payments over HTTP. It extends the HTTP 402 status code with a structured payment challenge/response flow:

• Server returns 402 with a PAYMENT-REQUIRED header (base64-encoded JSON) listing accepted payment schemes, token addresses, amounts, and chain identifiers.
• Client signs an off-chain authorization (EIP-3009 TransferWithAuthorization) and sends it back in a PAYMENT-SIGNATURE header.
• Server verifies the signature, submits the token transfer on-chain, and returns the requested resource along with a PAYMENT-RESPONSE header containing the transaction hash.

Security considerations

• Private keys — Your private key never leaves your machine. It is used only to sign an EIP-712 typed data message. No raw transactions are broadcast by the client.
• Confirmation — Every payment requires explicit y confirmation before signing.
• Amount visibility — The exact token amount, recipient, network, and your balance are displayed before you confirm.
• No blind signing — The EIP-712 domain and message fields are fully specified by the server's challenge and can be inspected.

License

MIT