onchain-pay-open-api

---
name: onchain-pay-open-api
description: |
  Binance Onchain Pay enables users to buy cryptocurrency with fiat (e.g., EUR, USD) or send existing crypto from their Binance account directly to any external on-chain wallet address in a single flow—no manual withdrawal needed.
  
  Enables partners to integrate crypto buying services:
  - payment-method-list: Get available payment methods (Card, P2P, Google Pay, Apple Pay, etc.) with limits for a fiat/crypto pair
  - trading-pairs: List all supported fiat currencies and cryptocurrencies
  - estimated-quote: Get real-time price quote including exchange rate, fees, and estimated crypto amount
  - pre-order: Create a buy order and get redirect URL to Binance payment flow
  - order: Query order status and details (processing, completed, failed, etc.)
  - crypto-network: Get supported blockchain networks with withdraw fees and limits
  - p2p/trading-pairs: List P2P-specific trading pairs
metadata:
  version: 0.1.2
  author: onchain-pay-team
license: MIT
---

# 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

| Endpoint | API Path | Required Params | Optional Params |
|----------|----------|-----------------|-----------------|
| Payment Method List (v1) | `papi/v1/ramp/connect/buy/payment-method-list` | fiatCurrency, cryptoCurrency, totalAmount, amountType | network, contractAddress |
| Payment Method List (v2) | `papi/v2/ramp/connect/buy/payment-method-list` | (none) | lang |
| Trading Pairs | `papi/v1/ramp/connect/buy/trading-pairs` | (none) | (none) |
| Estimated Quote | `papi/v1/ramp/connect/buy/estimated-quote` | fiatCurrency, requestedAmount, payMethodCode, amountType | cryptoCurrency, contractAddress, address, network |
| Pre-order | `papi/v1/ramp/connect/buy/pre-order` | externalOrderId, merchantCode, merchantName, ts | fiatCurrency, fiatAmount, cryptoCurrency, requestedAmount, amountType, address, network, payMethodCode, payMethodSubCode, redirectUrl, failRedirectUrl, redirectDeepLink, failRedirectDeepLink, customization, destContractAddress, destContractABI, destContractParams, affiliateCode, gtrTemplateCode, contractAddress |
| Get Order | `papi/v1/ramp/connect/order` | externalOrderId | (none) |
| Crypto Network | `papi/v1/ramp/connect/crypto-network` | (none) | (none) |
| P2P Trading Pairs | `papi/v1/ramp/connect/buy/p2p/trading-pairs` | (none) | fiatCurrency |

---

## 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
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`](./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`)

| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| fiatCurrency | string | Yes | Fiat currency code (e.g., `USD`, `EUR`, `BRL`, `UGX`) |
| cryptoCurrency | string | Yes | Crypto currency code (e.g., `BTC`, `USDT`, `USDC`, `SEI`) |
| totalAmount | number | Yes | Amount value |
| amountType | number | Yes | `1` = fiat amount, `2` = crypto amount |
| network | string | No | Blockchain network (e.g., `BSC`, `ETH`, `SOL`, `BASE`, `SEI`) |
| contractAddress | string | No | Token contract address (required for non-native tokens) |

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

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

| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| lang | string | No | Language code for localized payment method names (e.g., `en`, `cn`, `es`) |

**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`)

| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| fiatCurrency | string | Yes | Fiat currency code |
| cryptoCurrency | string | No | Crypto currency code (optional if contractAddress provided) |
| requestedAmount | number | Yes | Amount value |
| payMethodCode | string | Yes | Payment method (e.g., `BUY_CARD`, `BUY_GOOGLE_PAY`, `BUY_P2P`, `BUY_WALLET`) |
| amountType | number | Yes | `1` = fiat amount, `2` = crypto amount |
| network | string | **Yes*** | Blockchain network (can use default from `.local.md`) |
| contractAddress | string | No | Token contract address |
| address | string | **Yes*** | Destination wallet address for receiving crypto |

\* 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.

| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| externalOrderId | string | Yes | Partner's unique order ID (must be unique) |
| merchantCode | string | Yes | Merchant code assigned to you by Binance (provided by user) |
| merchantName | string | Yes | Merchant display name (provided by user) |
| ts | number | Yes | Current timestamp in milliseconds |
| fiatCurrency | string | No* | Fiat currency code (e.g., `TWD`, `USD`, `EUR`) |
| fiatAmount | number | No* | Fiat amount to spend |
| cryptoCurrency | string | No* | Crypto currency to buy (e.g., `USDT`, `BTC`, `ETH`) |
| requestedAmount | number | No* | Amount value (fiat or crypto based on amountType) |
| amountType | number | No* | `1` = fiat amount, `2` = crypto amount |
| address | string | No | Destination wallet address for receiving crypto |
| network | string | No | Blockchain network (e.g., `BSC`, `ETH`, `SOL`) |
| payMethodCode | string | No | Payment method code (e.g., `BUY_CARD`, `BUY_P2P`, `BUY_GOOGLE_PAY`, `BUY_APPLE_PAY`, `BUY_PAYPAL`, `BUY_WALLET`, `BUY_REVOLUT`) |
| payMethodSubCode | string | No | Payment method sub-code (e.g., `card`, `GOOGLE_PAY`, `WECHAT`) |
| redirectUrl | string | No | Success redirect URL |
| failRedirectUrl | string | No | Failure redirect URL |
| redirectDeepLink | string | No | Deep link for success (mobile apps) |
| failRedirectDeepLink | string | No | Deep link for failure (mobile apps) |
| customization | object | No | Custom configuration object (see Customization section below) |
| destContractAddress | string | No | Destination contract address (for Onchain-Pay Easy mode) |
| destContractABI | string | No | Contract ABI name (for Onchain-Pay Easy mode) |
| destContractParams | object | No | Contract parameters (for Onchain-Pay Easy mode) |
| affiliateCode | string | No | Affiliate code for commission tracking |
| gtrTemplateCode | string | No | GTR template code (e.g., `OTHERS`) |
| contractAddress | string | No | Token contract address (for non-native tokens) |

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

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

### Get Order (`order`)

| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| externalOrderId | string | Yes | The external order ID to query |

---

## 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

| Flag | Code | Type | Availability | Description | Use Case |
|------|------|------|--------------|-------------|----------|
| `LOCK_ORDER_ATTRIBUTES` | 1 | array | Open API ✓ | Lock specific order attributes so users cannot modify them. Values: `1`=fiat currency, `2`=crypto currency, `3`=amount, `4`=payment method, `5`=network, `6`=address, `7`=fiat amount, `8`=crypto amount | Fixed-parameter orders |
| `SKIP_CASHIER` | 2 | boolean | Open API ✓ | Skip the cashier page and proceed directly to payment. Reduces user friction in the checkout flow. | Streamlined payment experience |
| `AUTO_REDIRECTION` | 3 | boolean | Open API ✓ | Automatically redirect to `redirectUrl` after order completion without showing success page. | Seamless user experience |
| `HIDE_SEND` | 6 | boolean | Open API ✓ | Hide the "Send" tab in the UI. Useful when only buy flow is needed. | Buy-only integration |
| `SEND_PRIMARY` | 7 | boolean | Open API ✓ | Enable Send Crypto feature. If user's Binance balance is insufficient, auto-trigger buy flow first. | Send crypto to external address |
| `MERCHANT_DISPLAY_NAME` | 8 | string | Open API ✓ | Override the display name shown to users in the UI. | Custom branding |
| `NET_RECEIVE` | 9 | boolean | Open API ✓ | User receives net amount after deducting all fees. Total cost is more transparent. | Better UX for showing final received amount |
| `P2P_EXPRESS` | 10 | boolean | Open API ✓ | Enable P2P Express mode for faster P2P order matching. | Quick P2P transactions |
| `OPEN_NETWORK` | 11 | boolean | Web3 only | Allow users to select different networks. Default is locked to pre-selected network. **Note**: Currently only available for Web3 entrance, not available for Open API. | Multi-network support (Web3 only) |
| `ON_CHAIN_PROXY_MODE` | 12 | boolean | Open API ✓ | Enable Onchain-Pay Easy mode. After buying crypto, Onchain-Pay will execute smart contract interaction instead of direct withdrawal to user wallet. Requires `destContractAddress`, `destContractABI`, and `destContractParams`. | Fiat to Smart Contract integration |
| `SEND_PRIMARY_FLEXIBLE` | 13 | boolean | Open API ✓ | Flexible Send Primary mode with more options. | Advanced send crypto scenarios |

### Customization Examples

**Example 1: Basic Card Payment**
```json
{
  "customization": {}
}
```

**Example 2: Onchain-Pay Easy (On-Chain Proxy)**
```json
{
  "customization": {
    "ON_CHAIN_PROXY_MODE": true,
    "NET_RECEIVE": true,
    "SEND_PRIMARY": true
  },
  "destContractAddress": "0x128...974",
  "destContractABI": "depositFor",
  "destContractParams": {
    "accountType": 2
  }
}
```

**Example 3: Send Crypto**
```json
{
  "customization": {
    "SEND_PRIMARY_FLEXIBLE": true,
    "SEND_PRIMARY": true
  }
}
```

**Example 4: P2P with Auto Redirection**
```json
{
  "customization": {
    "AUTO_REDIRECTION": true,
    "P2P_EXPRESS": true
  }
}
```

**Example 5: Lock Order Attributes**
```json
{
  "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**
```json
{
  "customization": {
    "NET_RECEIVE": true,
    "SEND_PRIMARY": true
  }
}
```

**Example 7: Hide Send Tab**
```json
{
  "customization": {
    "HIDE_SEND": true
  }
}
```

**Example 8: Skip Cashier (Direct Payment)**
```json
{
  "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

```markdown
## 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:

```bash
# 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

```bash
# 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\"}"
```