Sponsored Batch Transactions

ev-reth supports an EIP-2718 transaction type, 0x76, for application-sponsored gas and atomic batches of EVM operations.

Use this transaction type when an application wants users to submit intents without holding the native gas token, or when a product flow needs several calls to succeed or fail together.

What It Adds

Capability	Description
Gas sponsorship	A sponsor account can pay gas for a transaction signed by another account
Batch calls	One transaction can execute multiple Call operations
Atomic execution	If any call reverts, the whole transaction reverts
Standard submission	Signed transactions are submitted through eth_sendRawTransaction
RPC visibility	Sponsored transactions expose a feePayer field in transaction and receipt responses

Regular Ethereum transactions still work. Use type 0x76 only for sponsored or batched flows.

Transaction Model

An EvNode transaction replaces the standard single to, value, and input fields with a list of calls:

type Call = {
  to: Address | null
  value: bigint
  data: Hex
}

The transaction also keeps EIP-1559-style fee fields:

type EvNodeTransaction = {
  chainId: bigint
  nonce: bigint
  maxPriorityFeePerGas: bigint
  maxFeePerGas: bigint
  gasLimit: bigint
  calls: Call[]
  accessList: AccessList
  feePayerSignature?: Signature
}

The executor is the account that signs the transaction intent. The executor remains the transaction from address and is visible to contracts as tx.origin.

The sponsor is optional. When a sponsor signs the transaction, ev-reth charges gas to the sponsor instead of the executor. Value transfers still come from the executor.

Batch Calls

Each call contains:

• to: target contract or account. Use null for contract creation.
• value: native token value sent with that call.
• data: calldata or contract creation bytecode.

Rules:

• calls must contain at least one item.
• Calls execute in order.
• Only the first call may be a contract creation (to: null).
• If any call fails, all state changes from earlier calls in the same transaction are reverted.

Example batch:

await evnode.send({
  calls: [
    { to: token, value: 0n, data: approveData },
    { to: router, value: 0n, data: swapData },
  ],
})

This pattern is useful for application flows such as approve-then-call, multi-step account setup, onboarding actions, and batched admin operations.

Sponsorship Flow

Sponsorship separates authorization from gas payment:

1. The executor builds the transaction with feePayerSignature empty.
2. The executor signs the transaction intent using the 0x76 signature domain.
3. The application validates the intent against its sponsorship policy.
4. The sponsor signs the same intent using the 0x78 sponsor domain.
5. The final signed transaction is submitted with eth_sendRawTransaction.

The sponsor signature binds to the executor address. A sponsor cannot reuse the same sponsor signature for a different executor.

For a user-facing application, the usual architecture is:

User wallet / app client
  signs executor intent
        |
        v
Application sponsor service
  checks policy and sponsor balance
  adds feePayerSignature
        |
        v
ev-reth JSON-RPC
  eth_sendRawTransaction

The sponsor pays gas up to gasLimit * maxFeePerGas. Any gas refund goes back to the sponsor. The executor only needs enough balance for value transfers in the batch.

JSON-RPC Behavior

Submit type 0x76 transactions with standard Ethereum JSON-RPC:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "eth_sendRawTransaction",
  "params": ["0x76..."]
}

When a sponsored transaction is returned by eth_getTransactionByHash, eth_getBlockByNumber, or related transaction APIs, ev-reth includes the recovered sponsor address as feePayer.

Receipts also include feePayer when sponsorship was used.

Validation

ev-reth validates type 0x76 transactions before admitting them to the txpool:

• The executor signature must be valid.
• The sponsor signature must be valid when present.
• The call list must be non-empty.
• Only the first call may create a contract.
• Sponsored transactions require the sponsor to have enough balance for gas.
• Unsponsored transactions require the executor to have enough balance for gas and value.

Client Support

Most Ethereum wallets and CLIs do not know how to encode transaction type 0x76. Use the JavaScript client for application code:

pnpm add @evstack/evnode-viem viem

See JavaScript Client for signing, batching, sponsorship, and serialization examples.