Stablecoins and transfers: USDT, USDC and the network

Most trading on crypto exchanges is priced in stablecoins: tokens designed to be worth one US dollar each. They are how money moves between exchanges and wallets without passing through a bank. They are simple to use and easy to send to the wrong place, almost always for the same reason: the network.

USDT and USDC

• USDT, issued by Tether, is the most widely traded. Almost every pair A9's bots trade is priced against it.
• USDC, issued by Circle, is the other large one, common on Solana and in wallets.

Both aim to hold one dollar, backed by reserves the issuer reports. In practice they trade within a fraction of a cent of a dollar most of the time. They are not bank deposits: holding one means relying on its issuer, and a stablecoin can briefly trade below a dollar when confidence in that issuer wavers.

One token, many networks

A stablecoin is not on one blockchain. The same USDT exists separately on BNB Chain, Ethereum, Tron, Solana and others. Each version lives only on its own network, and a transfer arrives only on the network it was sent on.

• BNB Chain uses the BEP-20 standard, and its addresses start with 0x.
• Solana addresses are a longer string of letters and digits, with no 0x.
• Ethereum addresses also start with 0x and look exactly like BNB Chain ones. That is the most common trap: the same address can exist on both networks, and a transfer on the wrong one lands somewhere the recipient is not watching.

When you withdraw from an exchange, it asks for the network as well as the address. The choice is part of the payment, not a detail.

How A9 takes a payment

A9 is paid only by transfers you send yourself, on one of two networks:

• USDT on BNB Chain (BEP-20). The easiest choice if your USDT is on OKX or Binance: withdraw it on the BEP-20 network straight to the address shown.
• USDC on Solana, from an exchange withdrawal or any Solana wallet.

There is no memo or reference field to fill in. Instead each checkout is given its own figure: the price less a small random amount, written to four decimal places, such as 8.7613 for something priced at 8.80. The figure is unique among open checkouts, so the amount itself tells A9 who paid. It is never above the price.

• A figure is valid for 24 hours, and stays reserved for three days after that, so that a late payment cannot be matched to someone else.
• An arrival within a cent of the figure is matched as a rounding difference.
• If an exchange takes its withdrawal fee off the amount, an arrival slightly short of the figure is still matched to you.
• An overpayment beyond that, a payment after the figure expired, or one on the other network is held for support rather than lost. Paste the transaction hash on the Arrived step, and A9 checks it; if needed, support matches it by hand.

Plans are bought in 30-day blocks and never renew by themselves. The platform fee on bot profits is collected the same way, once it reaches 10 USDT.

Sending from an exchange, step by step

1. On the exchange, choose withdraw, then the coin the checkout names: USDT for BNB Chain, USDC for Solana.
2. Choose the network the checkout names. On OKX and Binance, BNB Chain may appear as BSC or BEP20.
3. Paste the address from the checkout. Check the first and last few characters after pasting.
4. Enter the amount so that what arrives is the exact figure. Some exchanges show both the amount sent and the amount received after their fee; the received figure is the one that matters.
5. Keep the transaction hash the exchange gives you, in case support needs it.

Transfers on both networks usually confirm within a minute or two, but an exchange may hold a withdrawal for its own checks first.

Why the network matters beyond A9

• Fees. A transfer on BNB Chain or Solana costs cents. The same transfer on Ethereum can cost far more.
• Reach. An exchange supports some networks for each coin and not others. Sending on a network the receiving side does not support can leave funds stranded.
• Recovery. A transfer to the right address on the wrong network may be recoverable only by hand, and sometimes not at all.

A9 watches BNB Chain and Solana only. A transfer on any other network will not be seen.

A short checklist

• The coin and the network both match the checkout.
• The address is pasted, not typed, and checked at both ends.
• The amount received is the exact figure, before it expires.
• The transaction hash is saved until the payment shows as arrived.