Ideal for AI Agents needing seamless integration with paid API services using the x402 payment protocol. x402 is a payment protocol that enables the discovery, inspection, and calling of paid API endpoints using USDC on Base.

How do I install x402?

Run the command: npx killer-skills add legasicrypto/skale-hackathon/x402. It works with Cursor, Windsurf, VS Code, Claude Code, and 19+ other IDEs.

What are the use cases for x402?

Key use cases include: Discovering new paid services in the bazaar, Inspecting price, method, and input schema for paid API endpoints, Automating USDC payments for API requests using the x402 protocol.

Which IDEs are compatible with x402?

This skill is compatible with Cursor, Windsurf, VS Code, Trae, Claude Code, OpenClaw, Aider, Codex, OpenCode, Goose, Cline, Roo Code, Kiro, Augment Code, Continue, GitHub Copilot, Sourcegraph Cody, and Amazon Q Developer. Use the Killer-Skills CLI for universal one-command installation.

Are there any limitations for x402?

Requires USDC on Base for payments. Limited to services supporting the x402 payment protocol.

x402

Discover and call paid API endpoints with x402 payment protocol. Learn how to search the bazaar and make USDC payments on Base.

SKILL.md

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Upstream Repository Material

The section below is imported from the upstream repository and should be treated as secondary evidence. Use the Killer-Skills review above as the primary layer for fit, risk, and installation decisions.

Supporting Evidence

x402 Payment Protocol

Name: x402
Availability: InStock
Author: legasicrypto

Use the npx awal@latest 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:

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

Commands

Search the Bazaar

Find paid services by keyword using BM25 relevance search:

bash
1npx awal@latest x402 bazaar search <query> [-k <n>] [--force-refresh] [--json]

Option	Description
`-k, --top <n>`	Number of results (default: 5)
`--force-refresh`	Re-fetch resource index from CDP API
`--json`	Output as JSON

Results are cached locally at ~/.config/awal/bazaar/ and auto-refresh after 12 hours.

List Bazaar Resources

Browse all available resources:

bash
1awal x402 bazaar list [--network <network>] [--full] [--json]

Option	Description
`--network <name>`	Filter by network (base, base-sepolia)
`--full`	Show complete details including schemas
`--json`	Output as JSON

Discover Payment Requirements

Inspect an endpoint's x402 payment requirements without paying:

bash
1awal 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:

bash
1awal 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

bash
1# Search for weather-related paid APIs
2awal x402 bazaar search "weather"
3
4# Search with more results
5awal x402 bazaar search "sentiment analysis" -k 10
6
7# Check what an endpoint costs
8awal x402 details https://example.com/api/weather
9
10# Make a GET request (auto-pays)
11awal x402 pay https://example.com/api/weather
12
13# Make a POST request with body
14awal x402 pay https://example.com/api/sentiment -X POST -d '{"text": "I love this product"}'
15
16# Limit max payment to $0.10
17awal x402 pay https://example.com/api/data --max-amount 100000
18
19# Browse all bazaar resources with full details
20awal 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 (awal auth login <email>) with sufficient USDC balance (awal balance)

Error Handling

"Not authenticated" - Run awal 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 (awal balance to check)

x402 — x402 payment protocol skale-hackathon, community, x402 payment protocol, ide skills, paid API requests, USDC payments on Base, bazaar search, API endpoint inspection, npx awal commands, x402 workflow

About this Skill

Features

# Core Topics

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Core Value

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