Paymaster Addresses and Events

This page contains information on the addresses of the Circle Paymaster contracts, and the events the contracts emit during operation.

Paymaster addresses

You can access the permissionless paymaster contracts at the following addresses on supported blockchains:

Paymaster v0.7

Mainnet

Blockchain	Symbol	Paymaster contract address
Arbitrum	ARB	0x6C973eBe80dCD8660841D4356bf15c32460271C9
Base	BASE	0x6C973eBe80dCD8660841D4356bf15c32460271C9

Testnet

Blockchain	Symbol	Paymaster contract address
Arbitrum Sepolia	ARB-SEPOLIA	0x31BE08D380A21fc740883c0BC434FcFc88740b58
Base Sepolia	BASE-SEPOLIA	0x31BE08D380A21fc740883c0BC434FcFc88740b58

Paymaster events

This section explains the events from the Circle Paymaster and when they are emitted. You can use these events to debug or track the state after submitting a user operation (user op) to a bundler.

TokenPaymasterV07.sol and TokenPaymasterV08.sol

These files are the main contract of the Circle Paymaster that support EntryPoint v0.7 and v0.8. The primary functions they integrate are:

• _validatePaymasterUserOp: validates the user op and charges the prefund token from the sender before execution.
• _postOp: refunds the token back to the sender when the actual amount of tokens needed is known after execution.

UserOperationSponsored

The contract emits this event after the _postOp is executed and the prefund token (if any) is refunded.

Attributes

Name	Type	Description
token	IERC20	The ERC-20 token paid by the sender
sender	address	The sender address
userOpHash	bytes32	The hash of the user op
nativeTokenPrice	uint256	The price of 1 ether = 1e18 wei, denominated in token
actualTokenNeeded	uint256	The final transaction cost to the smart contract account (SCA), denominated in token
feeTokenAmount	uint256	The fee spread used to cover the slippage from exchanging USDC for ETH, denominated in token

Example

Using this transaction as an example, the userOperationSponsored event contains the following data:

Name	Type	Value
token	IERC20	0x0000000000000000000000001c7d4b196cb0c7b01d743fbc6116a902379c7238
sender	address	0x000000000000000000000000148cab4b1a7e8c23ae62967cfc8df6292ecf27a8
userOpHash	bytes32	cc6f71a0ba8d9b72e75c45fae7b830c403b46964eb1d3f8daa0b73d14e6c5b0d
nativeTokenPrice	uint256	3000000000
actualTokenNeeded	uint256	4551712
feeTokenAmount	uint256	0