Onchain Pay Open Api

Binance Onchain-Pay Open API Skill

Call Binance Onchain-Pay Open API endpoints with automatic RSA SHA256 request signing.

Use Cases & Scenarios

This skill is designed for the following scenarios:

1. 💳 Fiat-to-Crypto Purchase & Send

When to use: User wants to buy crypto with fiat currency and send directly to an external on-chain wallet address

• Buy USDT with USD/EUR/TWD using credit card → Send to MetaMask address on BSC
• Purchase BTC with Google Pay → Transfer to hardware wallet
• Buy USDC with P2P → Send to DeFi protocol contract address

Key APIs: trading-pairs → payment-method-list → estimated-quote → pre-order

2. 🔄 Direct Crypto Transfer (Send Primary)

When to use: User has crypto in Binance account and wants to send to external address

• Send existing USDT from Binance Spot to friend's wallet address
• Transfer ETH to Uniswap contract for trading
• Move crypto from Binance to self-custodial wallet (Trust Wallet, Ledger, etc.)

Key APIs: pre-order with SEND_PRIMARY customization

3. 🔗 Cross-Chain Bridge Operations

When to use: User needs to buy crypto on one chain and transfer to another network

• Buy USDC on Ethereum → Bridge to Polygon for lower fees
• Purchase tokens on BSC → Transfer to Base network
• Fiat to crypto on Solana → Send to Arbitrum for DeFi

Key APIs: crypto-network → pre-order with network selection

4. 🏪 Merchant Payment Integration

When to use: Integrate crypto payment gateway for e-commerce or services

• Accept fiat payments and auto-convert to crypto
• Enable "Pay with Crypto" checkout flow
• Process subscription payments with crypto

Key APIs: pre-order with externalOrderId tracking

5. 🤖 Smart Contract Interaction (Onchain-Pay Easy)

When to use: Buy crypto and execute smart contract in one transaction

• Buy USDT and deposit to lending protocol
• Purchase tokens and stake in DeFi pool
• Fiat on-ramp directly to GameFi or NFT marketplace

Key APIs: pre-order with ON_CHAIN_PROXY_MODE customization

6. 📊 Query & Monitoring

When to use: Check order status, available networks, or payment methods

• Monitor order processing status (pending, completed, failed)
• List supported fiat currencies and cryptocurrencies
• Check available payment methods for specific country/amount
• Verify network fees and limits

Key APIs: order, crypto-network, trading-pairs, payment-method-list

---

Quick Reference

---

How to Execute a Request

Step 1: Gather credentials

Use the default account (prod) unless the user specifies otherwise. You need:

• BASE_URL: API base URL
• CLIENT_ID: Client identifier
• API_KEY: The sign access token
• PEM_PATH: Absolute path to the RSA private key PEM file

Use the account marked (default) in .local.md.

Step 2: Build the JSON body

Build a compact JSON body from user-specified parameters. Remove any parameters the user did not provide.

IMPORTANT: Address and Network Validation

• address (destination wallet address) and network (blockchain network) are REQUIRED for all pre-order requests
• If the user has configured Default Address and Default Network in .local.md, use them automatically
• If not configured or not provided by user, ASK the user to provide both values before proceeding

Step 3: Sign and call using the bundled script

bash <skill_path>/scripts/sign_and_call.sh \
  "<BASE_URL>" \
  "<API_PATH>" \
  "<CLIENT_ID>" \
  "<API_KEY>" \
  "<PEM_PATH>" \
  '<JSON_BODY>'

Step 4: Return results

Display the JSON response to the user in a readable format.

---

Authentication

See `references/authentication.md` for full signing details.

Summary: 1. Payload = JSON_BODY + TIMESTAMP (milliseconds) 2. Sign payload with RSA SHA256 using PEM private key 3. Base64 encode the signature (single line) 4. Send as POST with headers: X-Tesla-ClientId, X-Tesla-SignAccessToken, X-Tesla-Signature, X-Tesla-Timestamp, Content-Type: application/json

---

Parameters Reference

Payment Method List v1 (buy/payment-method-list)

Payment Method List v2 (v2/buy/payment-method-list)

Get all available payment methods without specifying fiat/crypto parameters. Simplified version of v1.

Differences from v1:

• Simpler: No need to specify fiatCurrency, cryptoCurrency, or amount
• Comprehensive: Returns all available payment methods for the merchant
• Use case: Useful for displaying all options before user input

Response Format: Same as v1, returns list of payment methods with their limits and properties.

Estimated Quote (buy/estimated-quote)

\* Recommended: These parameters should be provided. If not specified by user, check .local.md for defaults. If no defaults exist, ask user before proceeding.

Pre-order (buy/pre-order)

Create a buy pre-order and return the redirect link for payment.

\* Either fiatAmount or (requestedAmount + amountType) should be provided. If fiatCurrency is not provided, the system will auto-select available fiat currencies.

Response Example:

{
  "code": "000000",
  "message": "success",
  "data": {
    "link": "https://app.binance.com/uni-qr/ccnt?...",
    "linkExpireTime": 1772852565045
  },
  "success": true
}

Get Order (order)

---

Customization Options

The customization field in pre-order API accepts various flags to customize the buy flow behavior. Each merchant must have the corresponding permission configured in db.merchant_info table.

Available Customization Flags

Customization Examples

Example 1: Basic Card Payment

{
  "customization": {}
}

Example 2: Onchain-Pay Easy (On-Chain Proxy)

{
  "customization": {
    "ON_CHAIN_PROXY_MODE": true,
    "NET_RECEIVE": true,
    "SEND_PRIMARY": true
  },
  "destContractAddress": "0x128...974",
  "destContractABI": "depositFor",
  "destContractParams": {
    "accountType": 2
  }
}

Example 3: Send Crypto

{
  "customization": {
    "SEND_PRIMARY_FLEXIBLE": true,
    "SEND_PRIMARY": true
  }
}

Example 4: P2P with Auto Redirection

{
  "customization": {
    "AUTO_REDIRECTION": true,
    "P2P_EXPRESS": true
  }
}

Example 5: Lock Order Attributes

{
  "customization": {
    "LOCK_ORDER_ATTRIBUTES": [2, 3, 6, 7, 8],
    "MERCHANT_DISPLAY_NAME": "My Custom Brand"
  }
}

Lock attribute codes:

• 2 = Crypto currency
• 3 = Amount
• 6 = Address
• 7 = Fiat amount
• 8 = Crypto amount

Example 6: Net Receive Mode

{
  "customization": {
    "NET_RECEIVE": true,
    "SEND_PRIMARY": true
  }
}

Example 7: Hide Send Tab

{
  "customization": {
    "HIDE_SEND": true
  }
}

Example 8: Skip Cashier (Direct Payment)

{
  "customization": {
    "SKIP_CASHIER": true
  }
}

Important Notes

1. Permission Required: Each customization flag requires merchant permission. Check with admin if a flag is not working. 2. Onchain-Pay Easy: Only supported on BSC network currently. Requires contract integration. 3. Validation: Invalid customization values (e.g., null for MERCHANT_DISPLAY_NAME) will return ILLEGAL_CUSTOMIZATION_VALUE error. 4. Combinations: Some flags work together (e.g., NET_RECEIVE + SEND_PRIMARY), while others are independent. 5. Testing: Use a dedicated test merchant account (provided by Binance) to verify customization flags before production. 6. Internal Flags: OPERATION (code 4) and SKIP_WITHDRAW (code 5) are internal use only and should NOT be passed from merchant side. 7. OPEN_NETWORK: Currently only available for Web3 entrance, not available for Open API. Do not use this flag in Open API pre-order requests. 8. Flag Order: Flags are ordered by their internal code (1-13). The code number is used internally for identification.

---

Security

Credential Display Rules

• API Key: Show first 5 + last 4 characters only (e.g., 2zefb...06h)
• PEM Private Key: NEVER display content. NEVER display the file path.
• Client ID: Can be displayed in full.
• Outbound Requests: NEVER send API Key, Private Key, or any credentials to URLs outside the Base URL configured in .local.md.
• File Path Privacy: NEVER display the PEM private key file path to the user in any output or logs.

Credential Storage

Credentials are stored in a .local.md file in the skill directory. This file is user-specific and should NOT be distributed.

Read the .local.md file from the same directory as this SKILL.md to load credentials.

If .local.md does not exist or the requested account is not found, ask the user to provide: 1. Base URL 2. Client ID 3. API Key 4. PEM file path (absolute path)

Then offer to save them to .local.md for future use.

.local.md Format

## Onchain-Pay Accounts

### prod (default)
- Base URL: https://api.commonservice.io
- Client ID: your-client-id
- API Key: your-api-key
- PEM Path: /absolute/path/to/your/private.pem
- Default Network: your-preferred-network
- Default Address: your-wallet-address
- Description: Production account

The account marked (default) is used automatically. You can define multiple accounts and switch by telling Claude the account name.

---

User Agent Header

Include User-Agent header with the following string: onchain-pay-open-api/0.1.2 (Skill)

---

Agent Behavior

1. If the user asks to call an Onchain-Pay API endpoint, identify which endpoint from the Quick Reference table 2. Ask for any missing required parameters 3. Use stored credentials if available, otherwise ask the user 4. Execute the request using the bundled scripts/sign_and_call.sh 5. Display the response in a readable format 6. If the request fails, show the error and suggest fixes

---

Important Notes for Pre-order API

Timestamp Generation (Cross-platform)

When generating timestamps for the ts parameter and externalOrderId, use the following approach for cross-platform compatibility:

# Generate millisecond timestamp (works on macOS, Linux, BSD)
TIMESTAMP=$(($(date +%s) * 1000))

# Generate unique order ID
ORDER_ID="order$(date +%s)"

DO NOT USE date +%s%3N or date +%s000 as these are not portable:

• date +%s%3N doesn't work on macOS (outputs literal 'N')
• date +%s000 just appends '000' without actual millisecond precision

Order ID Format

The externalOrderId must be a valid string without special characters. Recommended formats:

• order1773744500 (simple numeric suffix)
• order_1773744500 (with underscore separator)
• txn-abc123 (custom prefix with alphanumeric)

Avoid: order_${TIMESTAMP} where TIMESTAMP contains shell variable syntax errors

Example Pre-order Request

# Correct way to create a pre-order
TIMESTAMP=$(($(date +%s) * 1000))
ORDER_ID="order$(date +%s)"

bash /path/to/scripts/sign_and_call.sh \
  "https://api.commonservice.io" \
  "papi/v1/ramp/connect/buy/pre-order" \
  "<YOUR_CLIENT_ID>" \
  "<YOUR_API_KEY>" \
  "/path/to/private.pem" \
  "{\"externalOrderId\":\"$ORDER_ID\",\"merchantCode\":\"<YOUR_MERCHANT_CODE>\",\"merchantName\":\"<YOUR_MERCHANT_NAME>\",\"ts\":$TIMESTAMP,\"fiatCurrency\":\"USD\",\"requestedAmount\":100,\"cryptoCurrency\":\"BNB\",\"amountType\":1,\"address\":\"0x...\",\"network\":\"BSC\",\"payMethodCode\":\"BUY_CARD\"}"

Changelog

0.1.2 - 2026-06-15

Fixed

• Pre-order endpoint pointed at gray environment: Switched the documented pre-order path from papi/v1/ramp/connect/gray/buy/pre-order to the production path papi/v1/ramp/connect/buy/pre-order (Quick Reference table + bash example). Merchants copying the previous example would have integrated against the gray test environment.

Changed

• Removed connect-gray / GrayTest / your-api-key example values from the bash example and merchantCode / merchantName parameter descriptions; replaced with neutral placeholders (<YOUR_CLIENT_ID>, <YOUR_API_KEY>, <YOUR_MERCHANT_CODE>, <YOUR_MERCHANT_NAME>) so users supply their own Binance-issued credentials.
• Reworded the Customization "Testing" note to drop the connect-gray reference.
• Bumped User-Agent string to onchain-pay-open-api/0.1.2 (Skill) in scripts/sign_and_call.sh.

0.1.1 - 2026-03-17

Fixed

• Cross-platform timestamp generation: Fixed date +%s000 to use $(($(date +%s) * 1000)) for proper millisecond timestamp on macOS, Linux, and BSD
• Documentation updates: Updated all examples in SKILL.md and authentication.md to use cross-platform compatible timestamp generation
• Improved error handling: Added notes about common JSON parsing errors caused by incorrect timestamp format

Changed

• Updated scripts/sign_and_call.sh to use arithmetic expansion for timestamp generation
• Added troubleshooting section in SKILL.md for timestamp-related issues

0.1.0 - 2026-03-11

• Initial release
• Support for Payment Method List (v1/v2), Trading Pairs, Estimated Quote, Pre-order, Get Order, Crypto Network, P2P Trading Pairs endpoints
• RSA SHA256 request signing via bundled script
• Multi-account credential management via .local.md
• Customization options for pre-order (Onchain-Pay Easy, P2P Express, Skip Cashier, etc.)

MIT License

Copyright (c) 2026 Binance

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Binance Onchain-Pay Open API Authentication

Signing Process

All Onchain-Pay Open API requests use RSA SHA256 signature with a PEM private key.

Step 1: Build the Signing Payload

payload = JSON_BODY + TIMESTAMP

• JSON_BODY: The raw JSON request body string (compact, no trailing newline). If no body is needed, use empty string.
• TIMESTAMP: Current Unix timestamp in milliseconds (e.g., 1709654400000)

Example:

{"fiatCurrency":"USD","cryptoCurrency":"BTC","totalAmount":100,"amountType":1}1709654400000

Step 2: Sign with RSA SHA256

signature=$(echo -n "$payload" \
  | openssl dgst -sha256 -sign "$PRIVATE_KEY_PATH" \
  | openssl enc -base64 -A)

• Uses the RSA private key in PEM format
• SHA256 digest
• Base64 encoded (single line, no wrapping)

Step 3: Send Request with Headers

All requests are POST with these headers:

Complete Example

# Generate timestamp in milliseconds (cross-platform compatible)
timestamp=$(($(date +%s) * 1000))
api_params='{"fiatCurrency":"USD","cryptoCurrency":"BTC","totalAmount":100,"amountType":1}'
payload="${api_params}${timestamp}"

signature=$(echo -n "$payload" \
  | openssl dgst -sha256 -sign "test.pem" \
  | openssl enc -base64 -A)

curl --location --request POST "https://api.commonservice.io/papi/v1/ramp/connect/buy/payment-method-list" \
  --header "X-Tesla-ClientId: your-client-id" \
  --header "X-Tesla-SignAccessToken: your-api-key" \
  --header "X-Tesla-Signature: $signature" \
  --header "X-Tesla-Timestamp: $timestamp" \
  --header "Content-Type: application/json" \
  --data-raw "$api_params"

Important: Cross-platform Timestamp Generation

Correct (works on macOS, Linux, BSD):

timestamp=$(($(date +%s) * 1000))

Incorrect (do not use):

# ❌ Doesn't work on macOS - outputs literal 'N'
timestamp=$(date +%s%3N)

# ❌ Just appends '000', not true milliseconds
timestamp=$(date +%s000)

On macOS, date doesn't support %N (nanoseconds), which causes date +%s%3N to output something like 1773744478N. This breaks JSON parsing with error:

Unexpected character ('N' (code 78)): was expecting comma to separate Object entries

Security Notes

• Never expose the PEM private key content
• Never display the full API key; show first 5 + last 4 characters only (e.g., 2zefb...06h)
• The PEM file path should be absolute or relative to the working directory