1. What is USDT?
Tether(USDT) is a stablecoin issued by Tether Limited, 1 USDT= 1 USD.

2. What types of USDT are supported by imToken?
imToken supports following USDTs:

    • Omni USDT: based on Bitcoin, with the address starting with 1 or 3, and can be stored in a BTC wallet
    • ERC20 USDT: based on Ethereum, with the address starting with 0x and can be stored in ETH wallet
    • TRC20 USDT: based on Tron, with the address starting with T and can be stored in TRX wallet
    • USDT based on EVM chains: the address format is the same as ETH address, you need to switch to the corresponding EVM chain first, then you can manage these USDTs.
      • HECO USDT: based on the HECO network
      • BEP20 USDT: based on the Binance Smart Chain network
      • OKExChain USDT: based on the OKExChain network
      • Polygon USDT: based on the Polygon network
      • Other USDTs based on EVM chains

Note: Different types of USDTs cannot be transferred to each other’s blockchain. For example, Omni USDT cannot be transferred to Ethereum.

3. Why is the balance insufficient to pay the transaction fee?

    • Transferring Omni USDT requires at least 0.0001 BTC as the miner fee.
    • Transferring ERC20 USDT requires at least 0.001 ETH as the miner fee.
    • Transferring TRC20 USDT requires energy and bandwidth in the TRX wallet, or consuming a small amount of TRX as miner fees.
    • If you want to transfer USDT based on an EVM chain, you need the native token of the corresponding chains as the miner fee
      • Native token of HECO network: HT
      • Native token of BSC network: BNB
      • Native token of OKExChain network: OKT
      • Native token of Polygon network: MATIC

4. There is enough BTC in the wallet, but it still prompts "BTC balance is insufficient. Please add funds and re-initiate the transfer"

Please deposit about 0.0001 BTC into your BTC wallet main address, and then you can successfully initiate the transfer.

Omni USDT is based on the Bitcoin blockchain, and each Omni USDT transaction is accompanied by a transfer of 0.00000546 BTC to confirm identity and prevent dust attacks.

5. It prompts “You have an unmined BTC transaction. Please await 1 confirmation before re-initiating your transaction.” while transferring Omni USDT.

This is usually the case because UTXO in your BTC wallet is occupied (there are transactions not confirmed). You need to wait for the transaction to be added into the blockchain by miners, then you can initiate a new transaction.

6. How long does the transaction take to be confirmed?
It depends on the miner fee you set. The higher the miner fee you pay, the faster the transaction will be confirmed.

It usually takes 10 mins for an Omni USDT's transaction to be confirmed on blockchain. If you transfer USDT to an exchange, you usually need to wait for 2 block confirmations (i.e. about 20 minutes).

Note: The Omni USDT miner fee is higher than that of ERC20 USDT, TRC20 USDT and other EVM based USDTs.

7. How to set the miners fee?
imToken does not charge any transaction fees.

The transaction fees are charged by the miner who is responsible for adding your transaction into the blockchain. When you initiate a transfer with imToken, the wallet will automatically get the real-time optimal miners fee for you.

You can also adjust the miner fee on the transfer page by yourself. If you want a faster confirmation, imToken recommends you to set a higher miner fee.

Sometimes the optimal miner fees are not accurate due to poor network quality or blockchain nodes. In this case, you'd better check the real-time optimal transaction fees by yourself through these websites👇
Current best transaction fees by BTC: https://btc.com/stats/unconfirmed-tx
Current best transaction fees by ETH: https://etherscan.io/gastracker
Current best transaction fees by HECO: https://scan.hecochain.com/gasprice
Current best transaction fees by BSC: https://bscscan.com/gastracker
Current best transaction fees by Polygon: https://polygonscan.com/gastracker

8. A comparison of different types of USDTs

    • ERC20 USDT is widely used. Most exchanges support ERC20 USDT.
    • USDTs based on EVM chains are widely used, and each exchange often has its own recommended type of USDT with fast transfer speeds and low miner fees.
    • TRC20 USDT is widely used, with fast transfer speeds and low miner fees.
    • Omni USDT is the earliest USDT. Currently it is only used by a small number of people and the miner fees required to start a transaction is high and the transfer speed is slow.