Adds additional balance to one or more eligible validators and returns an unsigned transaction. Only withdrawal credentials of type 0x02 are supported. If a validator uses 0x01 credentials or if the combined value of the additional deposit and the validator's current effective balance exceeds 2048 ETH, the deposit will not be processed.

The unsigned transaction remains valid for up to 90 days or until it is signed and confirmed on the network.

Through the Blockdaemon batch deposit contract, a single transaction can top up up to 250 validators simultaneously, delivering over 50% gas fee savings compared to submitting separate transactions for each validator.

To complete the staking process, you must sign an Ethereum transaction with a data field set to match the returned unsigned_transaction property of the response. The recipient of the transaction must be set to the contract_address property of the response. The account signing the transaction must have the sufficient balance to top up the requested number of validators and this amount must be provided as the value of the signed transaction.