Default nonce key (Date.now()) costs ~99k extra gas per userOp after Glamsterdam (EIP-8037): default to a reused key?

[PyraVim]

Summary

toSmartAccount defaults nonceKeyManager to createNonceManager({ source: { get() { return Date.now() } } }) (account-abstraction/accounts/toSmartAccount.ts, viem 2.57.3), and getNonce uses nonceKeyManager.consume(...) as the key when the caller passes none. consume returns Date.now() or the previous value plus one, so every userOp gets a key that has never been used, with sequence 0.

In EntryPoint v0.7 the first use of a key writes a new storage slot (nonceSequenceNumber[sender][key]). Under EIP-8037 (Glamsterdam, live on Sepolia since 2026-10-06 13:53:36 UTC) a new slot costs 97,920 state gas. So with the default, every userOp now pays about 99k gas more for its nonce update than it would on a reused key. Before the fork the difference was about 17k. Each op also leaves a permanent slot in the EntryPoint, which is the state growth EIP-8037 prices.

This is a cost increase, not a failure, as long as verificationGasLimit is estimated per op on an Amsterdam node: bundler simulations include the nonce update. It turns into AA26 failures when an app hardcodes or caches verificationGasLimit.

Account implementations that pass the key through (for example permissionless.js toSafeSmartAccount, toSimpleSmartAccount, toBiconomySmartAccount, toThirdwebSmartAccount, toTrustSmartAccount, toLightSmartAccount: key: nonceKey ?? args?.key) inherit this default.

Measurement (Sepolia, EntryPoint v0.7 0x0000000071727De22E5E9d8BAf0edAc6f37da032)

EntryPoint.incrementNonce(uint192 key) performs the same storage write as a userOp's nonce update. Estimated from a fresh address, for a new key and for the same key with its sequence already at 1 (state override on nonceSequenceNumber[caller][key], mapping at base slot 1):

rules	new key	reused key	difference
after Glamsterdam (latest)	127095	28438	98657
before Glamsterdam (block 11856335, 13:53:12 UTC)	44370	27236	17134

Requests (results above from rpc.sepolia.ethpandaops.io, 2026-10-06T17:54:31.486Z). The "latest" requests work on any Sepolia node; the block 0xb4e9cf ones need a node that still has state for that block.

eth_estimateGas [{"from":"0xa2994cce779ffa927d31d94ad82b451b55331895","to":"0x0000000071727De22E5E9d8BAf0edAc6f37da032","data":"0x0bd28e3b0000000000000000337fd5dbba24717793816d59229576366757ab09a50a6d1f"},"latest"]
=> 0x1f077  (127095)

eth_estimateGas [{"from":"0xa2994cce779ffa927d31d94ad82b451b55331895","to":"0x0000000071727De22E5E9d8BAf0edAc6f37da032","data":"0x0bd28e3b0000000000000000337fd5dbba24717793816d59229576366757ab09a50a6d1f"},"latest",{"0x0000000071727De22E5E9d8BAf0edAc6f37da032":{"stateDiff":{"0x72651d863e1b78ea4ef669c99b51c4e6d92dfd7d1d72d755e72fde72b599deb5":"0x0000000000000000000000000000000000000000000000000000000000000001"}}}]
=> 0x6f16  (28438)

(same two requests with block "0xb4e9cf" instead of "latest")
=> 0xad52  (44370), 0x6a64  (27236)

0x72651d863e1b78ea4ef669c99b51c4e6d92dfd7d1d72d755e72fde72b599deb5 is keccak256(abi.encode(key, keccak256(abi.encode(caller, 1)))). The override dropping the estimate to 28438 confirms the slot.

Suggestion

Default to a reused key (for example key 0, or one stable key per account) when the caller does not ask for parallel nonces, and keep the timestamp key as an opt-in for parallel userOps. The timestamp default lets an app send several userOps without waiting, so this is a tradeoff. If the default stays, documenting that it opens a new nonce slot on every op and what that costs on Glamsterdam chains would help.

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Disclosure: prepared with the help of an AI assistant (Claude). The measurements and requests above were run against Sepolia and the output is pasted unedited.