Fordefi supports fee sponsorship across multiple chains. With fee sponsorship, a designated fee payer vault covers the transaction fees on behalf of the origin vault that initiates the transaction.
This is useful when you want to abstract gas costs away from your users or consolidate fee payments into a single vault.
| Chain | Example Script | Fee Payer Field | Additional Setup |
|---|---|---|---|
| EVM | Link to code | vault_id | Origin vault must be upgraded to an EIP-7702 smart account |
| Solana | Link to code | vault_id | None |
| Aptos | Link to code | vault_id | None |
| Sui | Link to code | vault_id | None |
Set up an API User and an API signer by following the Fordefi API Signer documentation.
You need 2 Fordefi vaults on the target chain:
- Origin vault: The vault initiating the transaction
- Fee payer vault: The vault that holds the gas token and will pay transaction fees on behalf of the origin vault
Enable fee sponsorship in your organization settings through the Fordefi web console. Fee sponsorship is always enabled via the Fordefi workspace settings (ask your workspace admin for help).
For EVM chains only, the origin vault must be upgraded to an EIP-7702 smart account before it can use fee sponsorship. The fee payer vault does not require any upgrade. See the EVM fee sponsorship code examples for details.
All sponsored transactions follow the same pattern across supported chains:
- Build a transaction request that includes a
details.fee_payerfield pointing to the fee payer vault - Sign the request payload with your API User's private key
- Broadcast the transaction via the Fordefi API
The fee_payer field is the key difference from a standard transfer:
"fee_payer": {
"type": "vault",
"vault_id": "<FEE_PAYER_VAULT_ID>"
}This field is added inside the details object of the transaction request body.