--- name: openkrill description: Enable AI agents to make micropayments via x402 protocol. Use when purchasing browser sessions on Browserbase, scraping with Firecrawl, or any x402-compatible API. Handles wallet creation, funding, and automatic payment flows. license: MIT compatibility: Requires network access and thirdweb API key (THIRDWEB_SECRET_KEY environment variable) metadata: author: emilankerwiik version: "1.2" openclaw: requires: env: - THIRDWEB_SECRET_KEY primaryEnv: THIRDWEB_SECRET_KEY ---

OpenKrill - x402 Payments Skill

This skill enables AI agents to autonomously make micropayments using the x402 protocol. It handles wallet management, balance checking, and automatic payment flows when APIs return HTTP 402 Payment Required responses.

When to Use This Skill

• When asked "what services can I purchase?" or "what x402 APIs are available?" - Query the Bazaar first!
• When purchasing browser automation sessions on Browserbase
• When performing web scraping tasks with Firecrawl
• When the agent needs to create an email address for signups or verification
• When interacting with any x402-compatible API
• When the user mentions micropayments, crypto payments, or paying for API access
• When you encounter a 402 Payment Required response
• When discovering new x402-compatible services via the Bazaar

> TIP: When a user or agent asks what services are available for purchase, always start by querying the Bazaar discovery endpoint. It provides a live, up-to-date catalog of 12,000+ x402-compatible services.

Quick: Discover Available Services

# Query the Bazaar to see what's available (no auth required)
curl -s "https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources?type=http&limit=50"

Prerequisites

Before using this skill, ensure:

1. THIRDWEB_SECRET_KEY environment variable is set with a valid thirdweb project secret key
2. The wallet has sufficient USDC balance on Base chain (or the target chain)
3. Network access to thirdweb API endpoints

IMPORTANT: x402 Endpoint URLs & Service Types

Two Types of x402 Support

| Type | Description | Example | |------|-------------|---------| | True x402 | Fully keyless - no API keys needed, just pay and use | Browserbase | | Hybrid x402 | Requires API key/token + payment header | Firecrawl |

x402 Endpoint Patterns

| Service | Standard API | x402 Endpoint | Type | Status | |---------|-------------|---------------|------|--------| | Browserbase | api.browserbase.com | x402.browserbase.com | True x402 | ✅ Works | | Firecrawl | api.firecrawl.dev/v1/search | api.firecrawl.dev/v1/x402/search | Non-standard | ❌ Broken |

Discovery tips:

• Check for x402. subdomain (e.g., x402.browserbase.com)
• Check for /x402/ in the path (e.g., /v1/x402/search)
• Hit the x402 root URL for endpoint listing (e.g., curl https://x402.browserbase.com/)

Core Workflow

Step 1: Check or Create Wallet

Use the thirdweb API directly (recommended):

curl -s -X POST https://api.thirdweb.com/v1/wallets/server \
  -H "Content-Type: application/json" \
  -H "x-secret-key: $THIRDWEB_SECRET_KEY" \
  -d '{"identifier": "x402-agent-wallet"}'

The response will include the wallet address. Store this for subsequent operations.

Step 2: Make Payments with fetchWithPayment

Call the thirdweb x402 fetch API directly:

# Browserbase - Create browser session
curl -s -X POST "https://api.thirdweb.com/v1/payments/x402/fetch?url=https://x402.browserbase.com/browser/session/create&method=POST" \
  -H "Content-Type: application/json" \
  -H "x-secret-key: $THIRDWEB_SECRET_KEY" \
  -d '{"browserSettings": {"viewport": {"width": 1920, "height": 1080}}}'

Step 3: Handle the Response

Success: The API returns the session data directly.

Insufficient Funds: If the wallet needs funding, the API returns:

{
  "result": {
    "message": "This endpoint requires 0.002 USDC on chain id 8453...",
    "link": "https://thirdweb.com/pay?chain=8453&receiver=0x...&token=0x..."
  }
}

When you receive a payment link, open it in the user's browser:

• If browser automation is available (MCP, browser tool, etc.), use it to navigate to the link in a new tab
• Otherwise, display the link prominently and instruct the user to open it manually

This opens thirdweb's payment page where users can fund the wallet.

API Reference

fetchWithPayment Endpoint

URL: https://api.thirdweb.com/v1/payments/x402/fetch

Method: POST

Query Parameters: | Parameter | Required | Description | |-----------|----------|-------------| | url | Yes | Target API URL to call | | method | Yes | HTTP method (GET, POST, etc.) | | from | No | Wallet address for payment (uses default project wallet if omitted) | | maxValue | No | Maximum payment amount in wei | | asset | No | Payment token address (defaults to USDC) | | chainId | No | Chain ID for payment (e.g., "eip155:8453" for Base) |

Headers:

• x-secret-key: Your thirdweb project secret key (required)
• Content-Type: application/json

Supported x402 Services

Browserbase

x402 Endpoint: https://x402.browserbase.com Pricing: $0.12/hour (paid in USDC on Base)

| Endpoint | Method | Description | |----------|--------|-------------| | /browser/session/create | POST | Create a browser session | | /browser/session/:id/status | GET | Check session status | | /browser/session/:id/extend | POST | Add more time | | /browser/session/:id | DELETE | Terminate session |

curl -s -X POST "https://api.thirdweb.com/v1/payments/x402/fetch?url=https://x402.browserbase.com/browser/session/create&method=POST" \
  -H "Content-Type: application/json" \
  -H "x-secret-key: $THIRDWEB_SECRET_KEY" \
  -d '{"browserSettings": {"viewport": {"width": 1920, "height": 1080}}}'

Firecrawl (Non-Standard x402 - NOT RECOMMENDED)

x402 Endpoint: https://api.firecrawl.dev/v1/x402/search Pricing: $0.01/request Status: ⚠️ Incomplete implementation - cannot be used with thirdweb

> WARNING: Firecrawl's x402 implementation is non-standard and currently unusable for automated agents: > > 1. Returns 401 Unauthorized instead of 402 Payment Required > 2. Doesn't include payment details (payTo address, asset, amount) in response > 3. Documentation says to use X-Payment: {{paymentHeader}} but doesn't explain how to generate it > > Comparison with proper x402 (Browserbase): > - Browserbase: Returns 402 with x402Version, accepts, payTo, asset → thirdweb can auto-pay > - Firecrawl: Returns 401 with just {"error":"Unauthorized"} → no payment info provided

| Endpoint | Method | Status | |----------|--------|--------| | /v1/x402/search | POST | ❌ Non-functional for agents |

Recommended alternatives:

1. Firecrawl MCP - If available in your environment (uses standard API key)
2. Browserbase + scraping script - True x402, fully keyless
3. Standard Firecrawl API - With subscription/API key

Reference: Firecrawl x402 docs

Mail.tm (Disposable Email)

Base URL: https://api.mail.tm Pricing: Free (no x402 payment required)

Mail.tm allows agents to create email addresses for signups and receive verification emails.

| Endpoint | Method | Auth | Description | |----------|--------|------|-------------| | /domains | GET | No | Get available email domains | | /accounts | POST | No | Create an email account | | /token | POST | No | Get authentication token | | /messages | GET | Yes | List all messages | | /messages/:id | GET | Yes | Get full message content | | /me | GET | Yes | Get account info |

Create Email Account

# 1. Get available domain
DOMAIN=$(curl -s https://api.mail.tm/domains | jq -r '.["hydra:member"][0].domain')

...