Ethereum

Post Top up Intent

Changed on Nov 3, 2026

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.

post/v1/ethereum/{network}/topup-intents

Request

Base URL
https://svc.blockdaemon.com/boss
URL
https://svc.blockdaemon.com/boss/v1/ethereum/{network}/topup-intents
Auth
API key in header X-API-KEY

Request body

Example request

{
  "top_ups": [
    {
      "public_key": "0xa1d1ad0714035353258038e964ae9675dc0252ee22cea896825c01458e1807bfad2f9969338798548d9858a571f7425c",
      "amount": "32000000000"
    }
  ]
}

Response

Created

network'mainnet' | 'hoodi' required

Ethereum network

contract_addressstring hex required

Hex-encoded Ethereum account or smart contract address.

estimated_gasinteger required

Gas estimation of the transaction

total_amountstring required

Amount of ETH (denominated in Gwei).

unsigned_transactionstring base64 required

Generated unsigned transaction smart contract call data.

expiration_timeinteger required

Transaction expiration time

Example response

{
  "contract_address": "0x00000000219ab540356cBB839Cbe05303d7705Fa",
  "estimated_gas": 1001,
  "total_amount": "32000000000",
  "unsigned_transaction": "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\n",
  "expiration_time": 1689939023,
  "top_ups": [
    {
      "public_key": "0xa1d1ad0714035353258038e964ae9675dc0252ee22cea896825c01458e1807bfad2f9969338798548d9858a571f7425c",
      "amount": "32000000000",
      "withdrawal_credentials": "0x0092c20062cee70389f1cb4fa566a2be5e2319ff43965db26dbaa3ce90b9df99",
      "fee_recipient": "0x00000000219ab540356cBB839Cbe05303d7705Fa"
    }
  ]
}

Changes

Nov 3, 20262c09b3ef4f99 Revision changes
- breaking
  the response's property type changed from string to integer, and format from no format to int32 for status
- breaking
  the response's property type changed from string to integer, and format from no format to int32 for status
- breaking
  the response's property type changed from string to integer, and format from no format to int32 for status
- warning
  removed the optional property from the response with the status
- warning
  removed the optional property from the response with the status
- warning
  removed the optional property from the response with the status

Operation history