Certain transaction parameters can affect the behavior and allocation of blockchain and transaction fees. The following lists provide additional details.

Vault accounts

• Transaction source: Your vault account.
• Transaction destination: Every transaction sent from your vault account requires a fee regardless of its destination.
• Fee source: The fee is taken from the same vault account that contains the transferred asset. When you have many vault accounts, you can use the Fireblocks Gas Station to automatically fuel your vault account with enough base assets to pay for future fees. This applies to all EVM-based blockchains.
• Fee selection options: 
  • A net vs. gross amount: the default is net amount.
  • Priority: High, Medium, or Low (Learn more about fee customization in the API documentation). 
  • Exact fee parameters: Custom.

Exchange accounts

• Transaction source: Your connected exchange account.
• Transaction destination: Several transaction types, such as from a main account to a sub-account, or from a sub-account to a sub-account, are considered off-chain transactions and do not require fees. Otherwise, every transaction from the connected exchange account to any other destination requires a fee.
• Fee source: The fee is taken from the same exchange account that contains the transferred asset. You can either transfer the base asset to your exchange account manually or trade between assets in your exchange account to have a sufficient amount for fees.
• Fee selection options: 
  • Only a gross amount.
  • Only a medium amount for the network fee. In addition, most exchanges charge a service fee for transactions made from one of their accounts.
  • No fee customization.

Gas multiplier

To prevent stuck transactions, Fireblocks applies a fixed multiplier to the gasLimit parameter for certain transaction types. The multiplier only affects EVM transactions in the following circumstances:

• All non-base asset token transfers to or from any account are 1.2x the estimated fee.
• All contract calls to or from any account are 1.6x the estimated fee.
• All transfers to an exchange account from any account are 2.6x the estimated fee.
• All transfers to an external whitelisted address from any account are 1.2x the estimated fee.

To disable this feature, contact your Customer Success manager.