getGaslessBatchSelectors

Build the selector set a session key must hold to relay a gasless batch — each relayable write’s selector, plus the wallet-execution sentinel and every inner call’s selector for each GaslessWallet entry.


import { getGaslessBatchSelectors, grantDelegation, relayGaslessBatch } from "@symmio/trading-core";
 
const calls = [
  { functionName: "allocate", args: [amount] },
  { walletCalls: [{ target: usdc, abi: erc20Abi, functionName: "transfer", args: [to, value] }] },
];
 
await grantDelegation(config, {
  account: { addr: subAccount, isPartyB: false },
  delegatedSigner: sessionKey,
  selectors: getGaslessBatchSelectors(calls),
  expiryTimestamp,
});
 
await relayGaslessBatch(config, { account: subAccount, calls, from: sessionKey });

Grant the set on the batch’s account: the InstantLayer checks a write’s selector there, and the GaslessLayer checks a wallet entry’s sentinel and inner selectors on the same account (a virtual account’s parent). The result is lowercased and de-duplicated in first-seen order, because grantDelegation rejects a duplicate-bearing array.

Selectors come from the encoded calldata, so an overloaded ABI resolves to the function that will actually run — and a named call is encoded against the SDK’s own ABI for the relayable write of that name.

A batch containing grantDelegation must be owner-signed whatever this returns: the InstantLayer rejects a delegate-signed grant. And the set is scoped to the batch — a key granted transfer can send the wallet’s whole balance to any recipient, because delegations bind selectors, not arguments. Grant the narrowest batch you can.

Parameters

callsreadonly GaslessBatchCall[]required

The batch, in any order and any of the call forms.

Returns

readonly Hex[]

The selector set to grant, as bytes4 hex.

Throws

SymmError("validation", "GASLESS_NOT_RELAYABLE") when a call without an abi names no relayable write.
Viem’s encoding error when an ABI-level call’s arguments do not encode.