x402

x402 Payment Protocol

Use the npx [email protected] x402 commands to discover, inspect, and call paid API endpoints using the X402 payment protocol. Payments are made in USDC on Base.

Workflow

The typical x402 workflow is:

1. Find a service - Search the bazaar or get details for a known endpoint
2. Check requirements - Inspect price, method, and input schema
3. Make the request - Call the endpoint with automatic USDC payment

Commands

Search the Bazaar

Find paid services by keyword using CDP's vector search:

npx [email protected] x402 bazaar search <query> [-k <n>] [--network <network>] [--scheme <scheme>] [--max-price <price>] [--json]

Option	Description
-k, --top <n>	Number of results, 1–20 (default: 20)
--network <name>	Filter by chain (base, base-sepolia, polygon, solana, solana-devnet)
--scheme <scheme>	Filter by payment scheme: exact or upto
--max-price <price>	Maximum price in USD (e.g. 0.01)
--asset <address>	Filter by payment asset address
--pay-to <address>	Filter by recipient wallet address
--extensions <type>	Filter by extension type (e.g. outputSchema, bazaar)
--json	Output as JSON

List Bazaar Resources

Browse all available resources:

npx [email protected] x402 bazaar list [--network <network>] [--full] [--refresh] [--json]

Option	Description
--network <name>	Filter by chain (base, base-sepolia, polygon, solana, solana-devnet)
--full	Show complete details including schemas
--refresh	Re-fetch resource index from CDP API
--json	Output as JSON

Discover Payment Requirements

Inspect an endpoint's x402 payment requirements without paying:

npx [email protected] x402 details <url> [--json]

Auto-detects the correct HTTP method (GET, POST, PUT, DELETE, PATCH) by trying each until it gets a 402 response, then displays price, accepted payment schemes, network, and input/output schemas.

Make a Paid Request

Call an x402 endpoint with automatic USDC payment:

npx [email protected] x402 pay <url> [-X <method>] [-d <json>] [-q <params>] [-h <json>] [--max-amount <n>] [--json]

Option	Description
-X, --method <method>	HTTP method (default: GET)
-d, --data <json>	Request body as JSON string
-q, --query <params>	Query parameters as JSON string
-h, --headers <json>	Custom HTTP headers as JSON string
--max-amount <amount>	Max payment in USDC atomic units (1000000 = $1.00)
--correlation-id <id>	Group related operations
--json	Output as JSON

Examples

# Search for weather-related paid APIs
npx [email protected] x402 bazaar search "weather"

# Search with more results
npx [email protected] x402 bazaar search "sentiment analysis" -k 10

# Check what an endpoint costs
npx [email protected] x402 details https://example.com/api/weather

# Make a GET request (auto-pays)
npx [email protected] x402 pay https://example.com/api/weather

# Make a POST request with body
npx [email protected] x402 pay https://example.com/api/sentiment -X POST -d '{"text": "I love this product"}'

# Limit max payment to $0.10
npx [email protected] x402 pay https://example.com/api/data --max-amount 100000

# Browse all bazaar resources with full details
npx [email protected] x402 bazaar list --full

USDC Amounts

X402 uses USDC atomic units (6 decimals):

Atomic Units	USD
1000000	$1.00
100000	$0.10
50000	$0.05
10000	$0.01

Prerequisites

• Search/Details: No authentication needed
• Pay: Must be authenticated (npx [email protected] auth login <email>) with sufficient USDC balance (npx [email protected] balance)

Error Handling

• "Not authenticated" - Run npx [email protected] auth login <email> first
• "No X402 payment requirements found" - URL may not be an x402 endpoint
• "CDP API returned 429" - Rate limited; cached data will be used if available
• "Insufficient balance" - Fund wallet with USDC (npx [email protected] balance to check)