What is paymaster?

A smart contract that pays a user's transaction fees, so someone can act on chain without holding the network's native coin.

It is a core piece of account abstraction and the mechanism behind wallets where an application sponsors your gas or lets you pay it in a stablecoin. On Ethereum the arrangement is specified in ERC-4337, which defines the paymaster role alongside user operations and bundlers (source: ERC-4337).

For a newcomer, it removes one of the most confusing steps in crypto, which is needing a second asset just to move the first. Being sent a stablecoin and being unable to touch it because you hold none of the chain's native coin is a genuinely common first experience.

How it works

Under account abstraction, a user does not send a transaction directly. They sign a user operation describing what they want done. A bundler collects these, wraps them into an actual transaction, and submits it. Someone still has to pay the network fee, and that is where the paymaster comes in.

A paymaster contract holds a deposit with the entry point contract and agrees to cover the fee for operations it approves. Two patterns dominate.

Sponsored gas. An application pays for its users' transactions outright, treating fees as a customer acquisition cost. The user pays nothing and may not even see a fee.

Token payment. The paymaster covers the network fee and takes payment from the user in a stablecoin or another token, usually at a small markup. The user's balance moves in the asset they actually hold.

Approval is conditional. The paymaster's code decides what it will pay for, and it can require a signature from the sponsor's server, restrict payments to specific contracts, cap amounts per user, or stop entirely. That is the dependency to understand: sponsorship is a service someone chooses to provide, not a property of the chain.

Several networks implement equivalent mechanisms natively rather than through a separate standard, so the user experience appears on chains beyond Ethereum.

Example

Illustrative first transaction. Someone receives $50 of a stablecoin into a new smart account wallet and wants to send $20 of it onward. They hold none of the chain's native coin.

Without a paymaster, the transfer cannot be sent at all, and the fix is to acquire a small amount of the native coin first, which usually means going back to an exchange. With a token-paying paymaster, the wallet quotes the fee in the stablecoin, say $0.35, deducts it from the $50 alongside the $20 transfer, and the paymaster pays the network in the native coin behind the scenes. The user never touches it.

Why it matters when you buy

This changes what you need to buy. On a chain and wallet that support it, you may not need to purchase the native coin separately just to move a stablecoin or an application token. Where support is absent, budgeting for a small amount of the native coin is still part of the plan. Which networks each exchange supports for withdrawals is recorded at the exchange directory, and network costs are measured on the chain rankings.

Related terms

• account abstraction — the model paymasters belong to
• erc 4337 — the standard defining the role
• gas — what is being paid on your behalf
• stablecoin — the usual payment asset
• smart contract — what a paymaster is
• intent — the related user-declares-outcome model

Questions

Does a paymaster mean transactions are free?

Not to the network. The fee is still paid, either by a sponsor absorbing the cost or by you in a different asset, usually with a small markup on top.

Can any wallet use one?

Only a wallet built as a smart account under account abstraction, on a chain that supports it. A traditional key-based account cannot use a paymaster and must hold the native coin.

Is it safe to let an application pay my fees?

The payment itself is low risk. What matters is what you are signing, since the user operation still authorizes whatever it describes. Sponsorship does not change the need to read the action being approved.