buildBridgeDeposit will build an unsigned USDT deposit from BOT Chain to another network, after checking the bridge’s live limits. You can build the same transaction today with viem.
Planned function
buildBridgeDeposit
The name comes from the SDK plan. Parameters and return types aren’t final. It’s planned to:- Read the pause state and limits, and throw
BridgeValidationErrorif the bridge is paused, the amount is outside the limits or the destination isn’t supported. - Return an unsigned call to the bridge router’s
deposit(destinationChainId, resourceId, recipient, amount), which you sign and send.
Bot gas
Bot gas gives a recipient a little BOT for gas when USDT arrives on BOT Chain. In plain words, from the verified BotBridge source:- Who asks for it. The sender calls
depositWithBotGasinstead ofdepositon the source chain. It takes the same four arguments. - What arrives. When the transfer lands on BOT Chain, the router works out what the configured BOT amount costs in USDT, using a time-weighted average price. It sends the recipient that BOT plus the rest of the USDT. With 0.1 BOT configured on mainnet, the recipient gets 0.1 BOT and slightly less USDT than a plain deposit.
- When it fails. If the USDT arriving is less than the BOT costs, or the price can’t be read, the delivery reverts on BOT Chain and has to be retried or refunded.
It doesn’t apply to deposits from BOT Chain
The router only accepts a bot gas deposit when the destination is the chain in the bot gas config, which is BOT Chain itself. A deposit from BOT Chain always goes somewhere else, sodepositWithBotGas is rejected. We confirmed this on testnet on 2026-10-02: simulating depositWithBotGas to BSC testnet (chain 97) reverted with invalid bot gas deposit.
So because v1 only supports BOT Chain as the source, buildBridgeDeposit will build plain deposit calls. Bot gas matters to you when your users bridge into BOT Chain through the official app at bridge.botchain.ai, which happens on the other chain.
Do it today
Bridge USDT out is a tested script that does everythingbuildBridgeDeposit will do: read limits, approve and call deposit. The core of it:
deposit-call.ts
tx to your wallet client’s sendTransaction after the USDT approval. Chain 97 is BSC testnet.
Related
Status and limits
Checks to run before building a deposit.
Track a transfer
Confirm it arrived.