Glossary
Paymaster
A contract that pays gas for someone else's user operation, so an account can transact without holding the chain's native token.
In ERC-4337 a user operation may name a paymaster. The paymaster contract is asked whether it will cover that operation and, if it agrees, the bundler is reimbursed from the paymaster's deposit rather than from the sender's balance. The sender may pay in a stablecoin instead, or not at all if someone is sponsoring.
For agents this removes an awkward bootstrapping problem: an agent funded in stablecoins can act without first being given native gas on every chain it touches. It also moves a decision — who is allowed to spend the sponsor's money — into contract logic that can be read.
A paymaster is a billing arrangement, not a permission. It decides who pays, never what the operation is allowed to do.
Where Sato Hub measures it
Numbers live on those pages and refresh on their own schedule; this definition does not restate them.
Related terms
Sources
Cite this page
Sato Hub. "Paymaster (glossary)." Sato Hub, updated 2026-09-14, accessed 2026-09-14. https://satohub.ai/glossary/paymasterData last refreshed 2026-09-14; this page is rebuilt daily. Citations carry the date so a reader can tell which snapshot a claim came from. Catalog data is licensed CC-BY-4.0.