Trading Authorization Guide for DEX API

Overview

Under the ERC-20 Token Standard, users must authorize the OKX DEX router to access their wallet assets before executing swap transactions. This API provides the necessary transaction details to initiate an approval request.

API Endpoint

GET https://web3.okx.com/api/v5/dex/aggregator/approve-transaction

Request Parameters

Parameter	Type	Required	Description
`chainId`	String	Yes	Chain ID (e.g., `1` for Ethereum; see full list).
`tokenContractAddress`	String	Yes	Token contract address (e.g., `0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48`).
`approveAmount`	String	Yes	Token amount to approve (include decimals; e.g., `1000000` for 1.00 USDT).

Response Parameters

Parameter	Type	Description
`data`	String	Call data for the transaction.
`dexContractAddress`	String	OKX DEX router contract address.
`gasLimit`	String	Gas limit (e.g., `50000`).
`gasPrice`	String	Gas price in wei (e.g., `110000000`).

Example Usage

Request Example

curl -X GET "https://web3.okx.com/api/v5/dex/aggregator/approve-transaction?chainId=1&tokenContractAddress=0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48&approveAmount=1000000"

Response Example

{
  "data": "0x...",
  "dexContractAddress": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
  "gasLimit": "50000",
  "gasPrice": "110000000"
}

FAQs

Why is token approval necessary?

Token approval ensures the DEX router can access the specified tokens in your wallet for swaps, adhering to ERC-20 security standards.

How do I calculate the correct `approveAmount`?

Multiply the token amount by its decimal precision (e.g., USDT uses 6 decimals: 1.00 * 10^6 = 1000000).

👉 Learn more about DEX APIs

Can I revoke an approval?

Yes, send a new transaction with approveAmount set to 0.

Key Takeaways

Always verify contract addresses before approving.
Use the gasLimit and gasPrice provided to avoid transaction failures.
Monitor blockchain explorers for transaction status.

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