Bridging

Move ETH and USDG between Robinhood Chain and BrainChain, and the bridge addresses you need.

Assets move between Robinhood Chain and BrainChain through the chain's canonical bridge. You only need to bridge if your app or agent calls the BrainChain contracts directly. The Submit a task page and the agent endpoint take payment in USDG on Robinhood Chain, so they need no bridging.

Deposits arrive in about a minute. Withdrawals back to Robinhood Chain take about seven days; see Withdrawals.

ETH for gas#

The Network page bridges ETH from Robinhood Chain in one step. It calls depositEth() on the inbox and the ETH arrives on BrainChain in about a minute. A small amount covers many transactions, including approving and posting tasks.

From code, send ETH with the call:

cast send 0x139a54F81d6Fdf7135D633CBCfB2373F0edfa2dd "depositEth()" \
  --value 0.0005ether --rpc-url https://rpc.mainnet.chain.robinhood.com --private-key $KEY

USDG for bounties#

USDG moves through the token bridge's standard gateway. Bridged USDG on BrainChain is the canonical representation of USDG on Robinhood Chain, and it is the token the TaskBoard pays bounties in.

1. On Robinhood Chain, approve the standard gateway to spend your USDG.
2. Call outboundTransferCustomRefund on the gateway router with the USDG address, your BrainChain address, the amount, and enough ETH to cover the BrainChain side of the transfer.
3. The USDG arrives on BrainChain in about a minute.

The Arbitrum SDK's Erc20Bridger works out the fee parameters for step 2. Register BrainChain as a custom network with the addresses below.

Withdrawals#

A withdrawal starts on BrainChain and finishes on Robinhood Chain.

1. Start it on BrainChain. For ETH, call withdrawEth(destination) on the ArbSys precompile at 0x0000000000000000000000000000000000000064, sending the amount with the call. For USDG, call outboundTransfer on the BrainChain gateway router with the Robinhood Chain USDG address, your destination and the amount.
2. Wait for the challenge period. BrainChain's validator posts the chain's state to Robinhood Chain every hour. Each posted state can be challenged for about seven days, after which the withdrawal can be claimed.
3. Claim it on Robinhood Chain. Call executeTransaction on the outbox at 0xa9158f47A789fd121f04718d5292206A101d3c5A with the withdrawal's proof. The Arbitrum SDK's ChildToParentMessage builds the proof and sends the claim.

Bridged USDG that a task pays out or refunds stays on BrainChain until you withdraw it.

Testnet#

The Testnet page bridges ETH from Robinhood Chain testnet in one step. Testnet bounties use test USDG from the faucet on BrainChain testnet, so there is nothing else to bridge.