Smart wallets explained: passkeys, gasless transactions and the future of DeFi UX

Smart wallets are crypto wallets controlled by code rather than by a single private key, and they make DeFi feel much more like a modern banking app. You can sign in with your fingerprint, skip buying gas tokens, and recover your account without a 12-word seed phrase.

For most of DeFi's history, using a wallet meant writing down a seed phrase, keeping a balance of ETH just to pay fees, and approving each step of a transaction one by one. These steps are a big reason many people try DeFi once and do not come back.

This guide explains what smart wallets are, the technology behind them (account abstraction), and the features they unlock: passkeys, gasless transactions, batched actions and easier recovery.

Regular wallets vs smart wallets

The difference comes down to who decides whether a transaction is valid: a single private key, or a set of rules written in code.

Most wallets people use today are externally owned accounts (EOAs). An EOA is controlled by one private key, usually backed up as a 12- or 24-word seed phrase. Whoever holds that key has full control, and the rules are fixed by the blockchain itself. Every transaction must be signed by that key, and fees must be paid in the chain's native token, such as ETH.

A smart wallet (also called a smart account or smart contract wallet) is an account whose behavior is defined by a smart contract. Because the contract is programmable, it can decide what counts as a valid signature, who pays the fees, and what limits apply.

Account abstraction: the technology behind smart wallets

Account abstraction is the idea that an account's rules (how it signs, pays fees and authorizes actions) should be set by code instead of being hard-wired into the blockchain. On Ethereum, two standards make it work today.

ERC-4337 brought smart accounts to Ethereum without changing the core protocol. Instead of sending a normal transaction, the wallet creates a UserOperation, a description of what the user wants to do. It then goes through a separate pipeline:

• 1. Create: the wallet creates and signs a UserOperation, for example “swap 100 USDC for ETH”.
• 2. Bundle: a bundler collects UserOperations from many users and submits them to the blockchain in one transaction.
• 3. Verify: the EntryPoint contract, a shared contract on-chain, checks each operation against its smart account's rules.
• 4. Pay (optional): a paymaster agrees to cover the gas fee, either for free or in exchange for another token.
• 5. Execute: the smart account carries out the action.

The paymaster is the piece that makes gasless transactions possible: it settles the fee with the EntryPoint so the user does not have to.

EIP-7702, introduced in Ethereum's Pectra upgrade in May 2025, takes a different route. It lets an existing regular wallet point to a smart contract and borrow its features, such as batching and sponsored fees. Users keep the same address and balances, so they get smart wallet features without moving funds to a new account. The two standards are designed to work together: EIP-7702 accounts can use the same bundlers and paymasters built for ERC-4337 (ethereum.org).

Passkeys: signing with your fingerprint or face

A passkey lets you approve a transaction the same way you unlock your phone, with Face ID, a fingerprint or a device PIN. There is no seed phrase to write down.

Passkeys are built on the WebAuthn standard, which many websites already use for passwordless login. When you create one:

• 1. Your device generates a key pair and keeps the private key in its credential manager, such as iCloud Keychain or Google Password Manager. Only the public key is shared with your smart wallet.
• 2. The private key is never shown to you or to the site you are signing into. A device-bound passkey stays in that device's secure hardware; a synced passkey is end-to-end encrypted and copied to your other devices, which is why the account it syncs through matters.
• 3. To sign, you confirm with your biometrics or PIN, and the chip produces a signature.
• 4. The smart wallet's contract checks that signature against the stored public key.

There was one technical gap. Passkeys use a cryptographic curve called secp256r1 (also known as P-256), while Ethereum accounts natively use a different curve, secp256k1. Verifying passkey signatures on-chain used to be slow and expensive. Ethereum's Fusaka upgrade in December 2025 added EIP-7951, a built-in function that verifies P-256 signatures cheaply, which makes passkey-based wallets far more practical (Chainstack). Many Layer 2 networks had already added the same support through RIP-7212.

That syncing is what stops a lost phone from meaning a lost wallet, and it is also the trade-off: a synced passkey is only as safe as the account it syncs through, so that account needs two-factor authentication of its own. A device-bound passkey is harder to lose control of and easier to lose outright, which is where a smart wallet's recovery rules earn their place.

Gasless transactions and paymasters

“Gasless” does not mean the fee disappears. It means someone or something other than you pays it, or you pay it in a token you already hold.

With a regular wallet, every transaction needs the chain's native token for gas. A new user who receives USDC cannot move it until they also buy some ETH. Paymasters solve this. A paymaster is a smart contract that agrees to cover the gas for a UserOperation under certain conditions. There are two common models:

• Sponsored transactions. An app pays the gas on the user's behalf, often for onboarding or for specific actions. The user pays nothing in fees.
• Pay gas in other tokens. The paymaster pays the fee in ETH and takes an equivalent amount of another token, such as USDC, from the user. The user never needs to hold ETH.

For the user, the experience becomes simple: confirm the action, and it happens. This is especially valuable on Layer 2 networks, where fees are low enough that sponsoring them is affordable for apps.

Other features smart wallets unlock

Because a smart wallet is programmable, it can do much more than sign. Four features stand out.

• Transaction batching. Several actions can run as one transaction with one confirmation. A swap that used to need an “approve” transaction followed by a “swap” transaction can happen in a single step. Either every action succeeds, or none of them do.
• Social recovery. You can name trusted guardians, such as a second device, a hardware wallet or a friend's wallet. If you lose access, a set number of guardians (for example, two out of three) can approve moving control to a new key. No single guardian can take over the account alone.
• Session keys. A session key is a temporary key with limited permissions, such as “can trade up to 100 USDC on this app for the next hour”. It lets games and trading apps run smoothly without asking you to confirm every action, while your main key stays untouched.
• Spending limits and rules. You can set daily limits, allowlist trusted addresses or add a time delay for large withdrawals. These are the same kinds of controls people expect from a bank account, enforced by code.

What this means for the future of DeFi

Smart wallets remove most of the steps that made DeFi feel technical. Put together, the features above change the experience in a few clear ways:

• Onboarding can take seconds: create an account with a passkey, with no seed phrase and no need to buy gas first.
• Everyday use gets simpler: one confirmation for a multi-step action, fees paid in the token you already hold.
• Security becomes more flexible: recovery options, spending limits and scoped permissions instead of a single key that controls everything.
• Existing users are not left behind: with EIP-7702, a regular wallet can gain these features while keeping its address.

There are still things to understand. Smart wallets rely on smart contract code, so the quality and auditing of that code matter. Passkeys synced to the cloud are only as secure as the cloud account. And because the standards are still young, features vary between wallet providers.

The direction is clear, though. Ethereum's recent upgrades have steadily added the building blocks for programmable accounts, and wallets are adopting them. The goal is a DeFi experience where the technology fades into the background and users simply see what they want to do.

Sources: ethereum.org, EIP-7702 for EIP-7702 and its compatibility with ERC-4337; EIP-7607, the Fusaka hardfork meta and EIP-7951 for the secp256r1 precompile; ethereum.org, history of Ethereum upgrades for the Pectra and Fusaka dates; Apple, about the security of passkeys for how passkeys sync.

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