Skip to main content
The HEVN platform does not operate on the user’s Privy EOA directly. Each account is a smart contract wallet on Base, built on Coinbase’s open-source, audited Smart Wallet contracts — the same contracts behind Base Account. The user’s Privy wallet is the initial owner of the smart wallet — and the only one, unless the user deliberately adds others. Only keys with owner rights or an owner-granted spend allowance can authorize spending; HEVN holds neither.

​
What the smart wallet gives you

Gasless USDC

Transact entirely in USDC — a paymaster sponsors gas, no ETH ever needed.

Deterministic addresses

Your address is known before deployment — send-by-email is safe by construction.

Shared access

Add co-owners or grant exact spend allowances, all enforced onchain.

Idempotent transfers

Every operation executes exactly once — a payout can never be sent twice.
All four are properties of the ERC-4337 account-abstraction standard and Coinbase’s wallet contracts — not HEVN-side logic that you would have to trust.

​
Gasless USDC transactions

Smart wallets follow ERC-4337 account abstraction: instead of raw transactions, they execute user operations that can be sponsored by a paymaster. HEVN sponsors gas through a paymaster (see Coinbase Developer Platform Paymaster), so users:
  • transact entirely in USDC,
  • never need to buy or hold ETH,
  • never see a “gas” concept at all.
Sponsoring gas gives HEVN no control over the wallet — a paymaster only pays fees; it cannot initiate or modify operations.

​
Deterministic (counterfactual) addresses

Smart wallet addresses are computed with CREATE2 from the owner key, before any contract is deployed. HEVN therefore knows the wallet address for every user — including users who haven’t signed up yet — which makes direct-to-wallet deposits and send-by-email safe. Funds sent to a counterfactual address are simply held by the address until the wallet is deployed on first use; they can never be redirected.

​
Native multi-user access

The wallet inherits Coinbase’s MultiOwnable contract (full co-ownership) and supports Spend Permissions (bounded allowances). HEVN uses these to let a user share an account with teammates — with full access or an exact spending limit. See Shared account access.

​
Idempotent transfers: no double-sends

Every action from the wallet is an ERC-4337 user operation carrying a unique nonce, validated by the canonical EntryPoint contract’s nonce manager (ERC-4337, “Semi-abstracted nonce support”). The EntryPoint accepts each (sender, nonce) pair at most once: once an operation executes, resubmitting it — by accident, by a retrying client, or by a malicious relayer — is rejected at the protocol level. HEVN builds on this for money movement. For each payout to a one-time withdrawal address — a banking-partner offramp or a 1Click swap — the client derives the operation’s nonce from that one-time deposit address. One address, one nonce, one possible execution:
  • If the app, the CLI, or the network retries a submission, the same operation lands at most once onchain.
  • A second transfer to the same one-time address would need the same nonce — which the EntryPoint has already consumed. Double-sending a payout is rejected by the wallet layer itself, not by HEVN’s backend deduplicating requests.
The platform API adds its own idempotency keys on top (see API authentication), but those protect metadata calls. For funds, the source of truth is the EntryPoint nonce check onchain.

​
Ownership, verifiable onchain

The ownership chain is public and auditable:
  1. The smart wallet contract stores its owners onchain (MultiOwnable keeps them as bytes — either an Ethereum address or a passkey public key).
  2. The user’s Privy address is registered as owner at deployment.
  3. Anyone can verify on Basescan that no HEVN-controlled key is an owner.
Every state change to the wallet — a transfer, an owner addition, an owner removal, or a contract upgrade — requires a valid signature from a current owner, validated by the wallet contract itself under the ERC-4337 EntryPoint. The wallet is Coinbase’s audited standard, deployed as-is: the upgrade mechanism it ships with (UUPS) is exercisable only by the wallet’s owners. HEVN holds no owner key, no upgrade key, no pause switch — the trust anchor for the contract layer is Coinbase’s public, audited code, not HEVN.

​
Contract addresses

Everything above is verifiable against the live deployment on Base: These are the canonical deployments from coinbase/smart-wallet and coinbase/spend-permissions — you can compare the verified bytecode on Basescan against the audited source in those repositories. Gas is sponsored through the Coinbase Developer Platform Paymaster.

​
References