Paying for x402 Services#

Use npx agnic@latest x402 pay to call x402-enabled API endpoints with automatic USDC payment on Base.

Authentication#

Run npx agnic@latest status --json to verify. If not authenticated:

• Headless (CI/server/agent): Set AGNIC_TOKEN env var or pass --token <token>
• Interactive (has browser): Run npx agnic@latest auth login

See the authenticate-wallet skill for details.

Command Syntax#

bash

npx agnic@latest x402 pay <url> [-X <method>] [-d <json>] [-q <params>] [-h <json>] [--max-amount <n>] [--json]

See reference/x402-protocol.md for full options, USDC amounts, and input validation rules.

Workflow#

1. Check requirements (optional but recommended): bash

   npx agnic@latest x402 details <url>
   
   

   Shows price, method, and schema without making a payment.

2. Verify balance: bash

   npx agnic@latest balance --network base
   
   

3. Make the paid request: bash

   npx agnic@latest x402 pay <url> --json
   
   

Examples#

bash

# GET request (auto-pays)
npx agnic@latest x402 pay https://example.com/api/weather --json

# POST request with body
npx agnic@latest x402 pay https://example.com/api/sentiment -X POST -d '{"text": "I love this product"}' --json

# Limit max payment to $0.10
npx agnic@latest x402 pay https://example.com/api/data --max-amount 100000 --json

Prerequisites#

• Must be authenticated ( npx agnic@latest status to check)
• Wallet must have sufficient USDC balance on Base

Error Handling#

Common errors:

• "Not authenticated" -- Run npx agnic@latest auth login or set AGNIC_TOKEN
• "Insufficient balance" -- Fund wallet with USDC ( npx agnic@latest balance to check)
• "No X402 payment requirements found" -- URL may not be an x402 endpoint
• Invalid JSON in --data -- Ensure the body is valid JSON before passing
• HTTP 4xx/5xx from the API -- Show the status code and response body to the user