X402 Layer

x402 Singularity Layer

x402 is a Web3 payment layer enabling AI agents to:

• 💰 Pay for API access using USDC
• 🚀 Deploy monetized endpoints
• 🔍 Discover services via marketplace
• 📊 Manage endpoints and credits
• 🔔 Webhooks — receive payment notifications

Networks: Base (EVM) • Solana
Currency: USDC
Protocol: HTTP 402 Payment Required

Quick Start

1. Install Dependencies

pip install -r {baseDir}/requirements.txt

2. Set Up Wallet (Choose One Mode)

Option A: Private Keys (existing mode)

# For Base (EVM)
export PRIVATE_KEY="0x..."
export WALLET_ADDRESS="0x..."

# For Solana (optional)
export SOLANA_SECRET_KEY="[1,2,3,...]"  # JSON array

Option B: Coinbase Agentic Wallet (AWAL)

For Base payments without exposing private keys, use Coinbase Agentic Wallet:

# First, install and set up AWAL (one-time setup)
npx skills add coinbase/agentic-wallet-skills

# Then enable AWAL mode for this skill
export X402_USE_AWAL=1

Note: See Coinbase AWAL docs for full setup instructions. You'll need to authenticate and fund your AWAL wallet with USDC on Base.

Once AWAL is configured, all Base payment scripts will automatically use it instead of PRIVATE_KEY.

⚠️ Security Notice

IMPORTANT: This skill handles private keys for signing blockchain transactions.

• Never use your primary custody wallet - Create a dedicated wallet with limited funds
• Private keys are used locally only - They sign transactions locally and are never transmitted
• Signed payloads are sent to api.x402layer.cc - Payment signatures and wallet addresses are transmitted to settle payments
• For testing: Use a throwaway wallet with minimal USDC ($1-5 is enough for testing)
• API Keys: When you create an endpoint, store the returned API key securely
• Review the code: All scripts are auditable in the scripts/ directory

Scripts Overview

🛒 CONSUMER MODE (Buying Services)

🏭 PROVIDER MODE (Selling Services)

Security: API Key Verification

[!IMPORTANT] When you create an endpoint, x402 acts as a proxy to your origin server. You MUST verify that requests are coming from x402.

1. Get your API Key: Returned when you run create_endpoint.py.
2. Verify Headers: Your origin server MUST check for this header in every request:

   x-api-key: <YOUR_API_KEY>
   

   If the header is missing or incorrect, reject the request (401 Unauthorized).

Credit System: How It Works

[!WARNING] Credits are NOT test credits! They are consumed with every API request.

Flow

User pays $0.01 → Your wallet receives payment → 1 credit deducted from your endpoint

Economics

Example

1. Create endpoint: Pay $1, get 4,000 credits
2. Set price: $0.01 per call
3. User calls your API 1,000 times: You earn $10, 1,000 credits deducted
4. Remaining: 19,000 credits + $10 profit
5. Credits run low? Recharge with topup_endpoint.py

What Happens When Credits = 0?

Your endpoint stops working and returns an error. Users cannot access it until you recharge.

Consumer Flows

A. Pay-Per-Request (Recommended)

# Pay with Base (EVM) - 100% reliable
python {baseDir}/scripts/pay_base.py https://api.x402layer.cc/e/weather-data

# Pay with Solana - includes retry logic
python {baseDir}/scripts/pay_solana.py https://api.x402layer.cc/e/weather-data

# Pay with Coinbase Agentic Wallet (AWAL)
python {baseDir}/scripts/awal_cli.py pay-url https://api.x402layer.cc/e/weather-data

B. Credit-Based Access (Fastest)

Pre-purchase credits for instant access without blockchain latency:

# Check your balance
python {baseDir}/scripts/check_credits.py weather-data

# Buy credits (consumer purchasing credits)
python {baseDir}/scripts/recharge_credits.py weather-data pack_100

# Use credits for instant access
python {baseDir}/scripts/consume_credits.py https://api.x402layer.cc/e/weather-data

C. Discover Services

# Browse all services
python {baseDir}/scripts/discover_marketplace.py

# Search by keyword
python {baseDir}/scripts/discover_marketplace.py search weather

# AWAL bazaar discovery
python {baseDir}/scripts/awal_cli.py run bazaar list

Provider Flows

A. Create Endpoint ($1 one-time)

Deploy your own monetized API:

Basic (not listed on marketplace):

python {baseDir}/scripts/create_endpoint.py my-api "My AI Service" https://api.example.com 0.01 --no-list

With marketplace listing (recommended):

python {baseDir}/scripts/create_endpoint.py my-api "My AI Service" https://api.example.com 0.01 \
    --category ai \
    --description "AI-powered data analysis API" \
    --logo https://example.com/logo.png \
    --banner https://example.com/banner.jpg

Available categories: ai, data, finance, utility, social, gaming

Note: Save the API Key from the output and use it to secure your origin server.

⚠️ IMPORTANT - How Credits Work:

• Cost: $1 one-time, includes 4,000 credits (NOT test credits!)
• Consumption: 1 credit is deducted for each API request to your endpoint
• When credits reach 0: Your endpoint stops working until you recharge
• Recharge: Use topup_endpoint.py to add more credits ($1 = 500 credits)
• Users pay YOU: Each user payment goes to your wallet, then 1 credit is used

Includes 4,000 starting credits.

B. Manage Your Endpoint

# List your endpoints
python {baseDir}/scripts/manage_endpoint.py list

# View stats
python {baseDir}/scripts/manage_endpoint.py stats my-api

# Update price
python {baseDir}/scripts/manage_endpoint.py update my-api --price 0.02

C. Recharge Your Endpoint (Required to Keep It Working)

Your endpoint consumes 1 credit per request. When credits run out, it stops working. Recharge to keep it active:

# Add $10 worth of credits (5,000 credits at 500 credits/$1)
python {baseDir}/scripts/topup_endpoint.py my-api 10

# Check remaining credits first
python {baseDir}/scripts/manage_endpoint.py stats my-api

⚠️ Remember: topup_endpoint.py is for providers to recharge THEIR endpoint. recharge_credits.py is for consumers to buy credits at someone else's endpoint.

D. Marketplace Listing Management

Marketplace listing can be done during creation OR separately afterward:

Option 1: During Creation (Recommended)

python {baseDir}/scripts/create_endpoint.py my-api "My API" https://api.example.com 0.01 \
    --category ai \
    --description "AI-powered analysis" \
    --logo https://example.com/logo.png \
    --banner https://example.com/banner.jpg

Option 2: After Creation (Update or List Later)

# List or update marketplace listing
python {baseDir}/scripts/list_on_marketplace.py my-api \
    --category ai \
    --description "AI-powered analysis" \
    --logo https://example.com/logo.png \
    --banner https://example.com/banner.jpg

# Unlist from marketplace
python {baseDir}/scripts/list_on_marketplace.py my-api --unlist

Tip: Use list_on_marketplace.py to update your listing anytime - change category, description, or images without recreating the endpoint.

E. Webhooks (Payment Notifications)

Receive payment.succeeded events when someone pays for your endpoint. Optional — not required for endpoints to work.

Set webhook at creation time:

python {baseDir}/scripts/create_endpoint.py my-api "My API" https://api.example.com 0.01 \
    --webhook-url https://my-server.com/webhook

Add or update webhook on existing endpoint:

python {baseDir}/scripts/manage_webhook.py set my-api https://my-server.com/webhook

Check webhook status:

python {baseDir}/scripts/manage_webhook.py info my-api

Remove webhook:

python {baseDir}/scripts/manage_webhook.py remove my-api

⚠️ IMPORTANT: The signing_secret is returned only once when you set a webhook. Save it immediately.

Webhook Event Types

Your endpoint receives POST requests with:

Content-Type: application/json
X-X402-Event: <event_type>
X-X402-Signature: t=<timestamp>,v1=<hmac_sha256>

payment.succeeded example:

{
  "id": "event-uuid",
  "type": "payment.succeeded",
  "created_at": "2026-01-01T00:00:00.000Z",
  "data": {
    "source": "endpoint",
    "source_slug": "my-api",
    "amount": 0.01,
    "currency": "USDC",
    "tx_hash": "0x...",
    "payer_wallet": "0x...",
    "network": "base",
    "status": "confirmed"
  }
}

credits.depleted example:

{
  "type": "credits.depleted",
  "data": {
    "source": "endpoint",
    "source_slug": "my-api",
    "remaining_credits": 0,
    "message": "Endpoint credits exhausted. Top up to resume service."
  }
}

credits.recharged example:

{
  "type": "credits.recharged",
  "data": {
    "source": "endpoint",
    "source_slug": "my-api",
    "credits_added": 5000,
    "previous_balance": 0,
    "new_balance": 5000,
    "amount_paid": 10,
    "currency": "USDC"
  }
}

Verify Webhook Signature

import hmac, hashlib
def verify(secret, timestamp, body, received_sig):
    expected = hmac.new(secret.encode(), f"{timestamp}.{body}".encode(), hashlib.sha256).hexdigest()
    return hmac.compare_digest(expected, received_sig)

When credits = 0, no requests go through, so no payments happen and no webhook events fire. Self-regulating.

Payment Technical Details

Base (EVM) - EIP-712 Signatures

Uses USDC TransferWithAuthorization (EIP-3009):

• Gasless for payer
• Facilitator settles on-chain
• 100% reliable

Solana - Versioned Transactions

Uses VersionedTransaction with MessageV0:

• Facilitator pays gas (from extra.feePayer)
• SPL Token TransferChecked instruction
• ~75% success rate (retry logic included)

Environment Reference

API Base URL

• Endpoints: https://api.x402layer.cc/e/{slug}
• Marketplace: https://api.x402layer.cc/api/marketplace
• Credits: https://api.x402layer.cc/api/credits/*
• Agent API: https://api.x402layer.cc/agent/*

Resources

• 📖 Documentation: studio.x402layer.cc/docs/agentic-access/openclaw-skill
• 💻 GitHub Docs: github.com/ivaavimusic/SGL_DOCS_2025
• 🐦 OpenClaw: x.com/openclaw
• 🌐 x402 Studio: studio.x402layer.cc

Known Issues

⚠️ Solana payments have ~75% success rate due to facilitator-side fee payer infrastructure issue. Retry logic is included in pay_solana.py. Base (EVM) payments are 100% reliable and recommended for production.