A paymaster is a smart contract in the account abstraction stack that holds funds for sponsoring transactions. It pays gas for user operations submitted to a bundler.

Is gasless the same as free?

Free from the user's perspective, yes. The network still gets paid — someone else (the platform, an app, or a third party) covers the gas via the paymaster.

Can any app offer gasless transactions?

Any app integrated with an account abstraction wallet stack on a chain that supports ERC-4337 (or native account abstraction) can offer it. Most L2s qualify.

Why would a platform pay my gas for free?

Because the platform earns enough per user (from trading fees, subscription, or other revenue) to cover the sponsored gas. It is an operating expense to reduce onboarding friction.

Can the paymaster refuse to sponsor my transaction?

Yes. Paymasters can apply rules — allowlists, rate limits, action restrictions. If a paymaster refuses, you can still submit the transaction yourself by paying gas in the normal way.

what is a gasless transaction and how paymasters work

For the entire history of Ethereum until basically last year, the rule was: to do anything on-chain, you needed ETH. To buy a token, ETH. To swap, ETH. To open a perp, ETH. Even if the thing you wanted to do had nothing to do with ETH, you needed ETH for gas. That requirement is the most common reason normies bounce off crypto in the first ten minutes.

Gasless transactions are how that requirement is being killed. The mechanism is called a paymaster. This is the explainer for what gasless actually means, how paymasters work, and why this is one of the most important ux unlocks in crypto right now.

the simple definition

A gasless transaction is an on-chain transaction where the user does not pay the gas fee directly. Instead, a third-party smart contract called a paymaster pays the gas on the user's behalf, and the user's transaction is processed normally by the network.

The blockchain itself does not skip the fee. Gas is still consumed. Validators still get paid. The difference is who funds the payment. From the user's perspective, the transaction appears free.

how it actually works

Paymasters live inside the account abstraction stack (ERC-4337 and its descendants). The flow is mechanical.

User initiates an action in the app. The app builds a "user operation" describing the action.
The user operation specifies a paymaster contract address. That paymaster has been pre-funded with ETH (or whatever the gas token is).
The user signs the operation with their key. They never need to hold ETH themselves.
A bundler picks up the operation and submits it as a regular transaction.
The paymaster contract pays the gas for the user operation. The action executes on-chain as if the user had paid gas directly.

There are variations. Some paymasters sponsor gas for free as user acquisition. Some charge the user in a non-ETH token (like USDC). Some require the user to be allowlisted. The mechanism is the same. The economics differ.

three types of paymaster

Sponsored paymaster: the app or platform pays the gas. User pays nothing. Common in onboarding flows.
Token paymaster: the user pays gas in a token other than ETH (USDC, the platform's own token, etc). Common in DEX integrations.
Hybrid paymaster: free up to a daily limit, then user pays. Common in production apps that want to limit subsidy cost.

why it matters for traders

For a perp trader on an L2, gas is small but constant. Opening a position, adding margin, closing, claiming — every action costs a fraction of a dollar. Sounds trivial until you realize the friction is not the money, it is the prerequisite. To pay gas you need ETH. To get ETH you need to onramp or bridge. That is a ten-minute detour every new user has to take before they can trade.

New users can deposit USDC straight from any chain or onramp and start trading immediately. No ETH on Base needed.
High-frequency tappers do not need to refill gas every few days. The paymaster handles it.
Failed transactions do not strand gas in the user's wallet — the paymaster covers them, win or lose.

In aggregate, gasless cuts the onboarding funnel from minutes to seconds. That is why every consumer crypto app shipped in 2025 sponsors gas by default.

Gasless is not "free for the network". Someone pays. The interesting design question is who, and how the economics close.

common misconceptions

A handful of common confusions about gasless and paymasters.

"Gasless means the chain skips fees." Wrong. The chain still gets paid. The paymaster funds the payment.
"Gasless is centralized." The paymaster is a smart contract. Its operator can be anyone, including a DAO. Centralization is a deployment choice, not a property of the model.
"Gasless transactions are slower." No. They process at the same speed as any other transaction once the bundler submits them.
"Gasless transactions can be censored." A paymaster can refuse to sponsor specific operations, but the user can always submit their own transaction if they have gas. Censorship resistance is preserved at the protocol level.
"Gasless is only useful for noobs." Not true. Power users benefit from never having to worry about gas balances across L2s. It is a quality-of-life improvement at every skill level.

when sponsored gas is sustainable

A platform sponsoring gas indefinitely loses money. So when is it sustainable? Three structural conditions.

L2 gas is cheap enough that sponsorship per user is fractions of a cent. Base, Arbitrum, Optimism, Linea all qualify.
The platform earns enough per active user to cover the sponsored gas plus margin. A perp arcade earning on trades, a swap app earning on volume, etc.
The platform can rate-limit or token-gate to prevent abuse (one bot draining the paymaster).

When all three hold, sponsored gas is just an operating expense and works fine. When they do not, the platform usually shifts to a token paymaster or rate-limited sponsorship.

gasless on different chains

Gasless support varies by chain. Ethereum mainnet can technically do it but the gas cost makes sponsoring expensive. L2s are where the model thrives: Base, Arbitrum, Optimism all support ERC-4337 with healthy paymaster ecosystems. Newer chains like Sei, Monad, Hyperliquid have their own variations. The pattern is the same: cheap blockspace plus account abstraction equals gasless ux.

For the broader smart wallet context, see what is a smart wallet. For why Base is the dominant venue for this pattern, see what is base the l2.

where uponly.win fits in

uponly.win sponsors gas for every trader. You can deposit USDC and start trading without ever touching ETH on Base. Our paymaster covers gas for opens, closes, and adjustments. The economics work because we earn a small variable cut on net winnings, which more than covers the gas subsidy per active user.

The reason we chose to sponsor gas instead of charging a token paymaster fee is that arcades live and die on time-to-first-tap. If a new user has to bridge ETH before they can rip, that is a thirty-minute funnel and most of them will not come back. With gasless, they tap rip ten seconds after landing. The button is at uponly.win.