Generating Subscription Transaction Call Data

Overview

This API provides call data for subscription transactions, enabling seamless integration with DeFi platforms. It facilitates the creation of transaction data required for subscribing to investment products.

API Endpoint

POST https://web3.okx.com/api/v5/defi/transaction/subscription

Request Parameters

Parameter	Description	Type	Required	Data Type
`address`	User wallet address	Body	Yes	String
`investmentId`	Investment product ID	Body	Yes	String
`userInputList`	User-input token details	Body	Yes	Array
`chainId`	Blockchain ID (default: product network)	Body	No	String
`coinAmount`	Subscription amount	Body	Yes	String
`tokenAddress`	Token contract address (default: product token)	Body	No	String
`expectOutputList`	Expected output details	Body	Yes	Array
`extra`	Additional metadata (see notes)	Body	No	String

Key Notes:

extra Field:
Used for specific cases like STX staking investments.
Example: rewardAddress (String) specifies the BTC reward wallet address for the user.

Response Parameters

Parameter	Description	Data Type
`dataList`	Call data details	Array
`from`	Sender address (user)	String
`to`	Recipient address (contract)	String
`value`	Native token transfer amount	String
`serializedData`	Call data payload	String
`originalData`	Raw JSON transaction data	JSON
`callDataType`	Action type (authorize/subscribe/redeem/claim)	String
`signatureData`	Signature for data verification	String

Signature Verification:

Derive r, s, v from signatureData.
Generate a hash using concatenated to + serializedData + originalData.
Validate with recovered public key.
(Optional but recommended for ensuring OKX-generated data authenticity.)

Example Usage

Request

{
  "address": "0x123...abc",
  "investmentId": "defi_pool_001",
  "userInputList": [
    {
      "chainId": "1",
      "coinAmount": "100",
      "tokenAddress": "0x456...def"
    }
  ],
  "expectOutputList": [
    {
      "chainId": "1",
      "coinAmount": "105",
      "tokenAddress": "0x456...def"
    }
  ],
  "extra": "rewardAddress=0x789...xyz"
}

Response

{
  "dataList": [
    {
      "from": "0x123...abc",
      "to": "0x987...ijk",
      "value": "",
      "serializedData": "0xabcd...1234",
      "originalData": "{...}",
      "callDataType": "subscribe",
      "signatureData": "0xsignature..."
    }
  ]
}

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FAQ

1. What is call data in DeFi transactions?

Call data contains encoded instructions for smart contracts, including method calls and parameters. It’s essential for executing transactions on-chain.

2. Why is signature verification optional?

While it ensures data authenticity, some integrations may prioritize speed over validation. However, we recommend enabling it for security.

3. How do I handle failed transactions?

Check the originalData field for error details and ensure gas fees are sufficient for the network.

4. Can I use this API for non-subscription transactions?

No, this endpoint is specifically designed for subscription workflows. Use other API endpoints for redemption or authorization.

5. What chains are supported?

Currently supports Ethereum-compatible chains (chainId=1). Check documentation for updates on additional networks.

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