Bridge
SANDchain Testnet currently supports the ZKsync Bridge. The Testnet version of the bridge allows for supported ERC20 tokens to be bridged between Silica (SANDchain Testnet) and Sepolia (Ethereum Testnet). With SAND being the token initially supported.
To access the bridge, you can either navigate there directly (https://sandchain-bridge.caldera.xyz/bridge) or by clicking on the applicable link in the SANDchain Caldera Hub.
Using the Bridge
At the launch of the testnet, the bridge will only support bridging of Testnet SAND between the Ethereum and SANDchain Testnets.
To use the bridge, you will first need to connect a supported wallet. Although the bridge does support a number of wallet choices, we recommend Metamask at this stage to ensure that you have full compatibility with SANDchain.
In this guide scenario, we will consider that the goal is to send SAND to Sepolia. So from SANDchain to Ethereum.
Connect Wallet - this wallet will be the sender
In the “From” panel select “Silica”, and this will automatically set the “To” panel to “Sepolia”
If you are not already connected to the appropriate network (in this case Silica), click “Change wallet network to Silica”. This will automatically change the network for the connected wallet.
Although these are testnet transactions, they still require transaction fees to be paid. If sending from Silica, then SAND is required. If sending from Sepolia, then ETH is required. For reference: the “Max” in the “From” field represents the total amount of SAND which can be bridged as it already considers the transaction fee.
Choose which wallet address on Sepolia you wish to receive the testnet SAND - by default it will be set to the connected wallet address
Input either an ENS or the wallet address if different to the sending wallet address
Input the amount of SAND you want to bridge in the “From” panel
Click “Continue”
When you use ZKsync Bridge to transfer out of SANDchain, the SAND bridged will not be automatically deposited into your wallet. You will need to manually claim the SAND once it is ready. This claim transaction requires a transaction fee to be paid.
Click “I understand, proceed to withdrawal”
Click “Bridge Now”
Once you have approved the transaction on your connected wallet, the bridging transaction is submitted.
Claiming Bridged Tokens
You can monitor the status of the bridging transaction in the bridge UI, but you do not need to stay on this page or keep it open. Closing the page once the transaction is confirmed, will not affect the transaction.
Once the transaction is complete, you will see "Go to Claim", and you can claim the bridged tokens.
In the Bridge, click "Transfers"
Click "Go to Claim"
If your wallet is not connected to the claiming network (Sepolia in this case), click "Change Network to Claim"
Click "Claim Withdrawal"
Confirm the transaction from your connected wallet
Once confirmed, and the transaction is complete, the bridge tokens will be received in the claiming wallet.
Bridging to SANDchain
The bridging to SANDchain is much the same flow as bridging from SANDchain. The only difference is that when bridging into SANDchain, you do not need to claim the bridged tokens, they are automatically deposited into your destination wallet address.
Although you do not need to claim and pay a transaction fee to claim tokens bridged into SANDchain, you will need SAND for any further transactions you intend to do. If using testnet, you can utilise the SANDchain faucet.
Token Approval Limits
If you have never used the bridge before you will be required to approve a SAND spend limit in your wallet, so that the bridge has permission to transfer your SAND.
Click “Approve SAND Allowance”
Click “Confirm” in your connected wallet - the “Allowance” here being referred to as the “Spending cap”
Once confirmed, the bridge will now be able to transfer your SAND tokens to the amount which you approved.
Last updated