AVNU Paymaster

Overview

StarkFi integrates with the AVNU Paymaster to enable gas abstraction on Starknet. This allows users to transact without holding native STRK for gas fees.

Two Modes

StarkFi supports two mutually exclusive gas abstraction modes. Only one can be active at a time.

Gasfree (Developer Sponsors Gas)

The developer pre-funds the Paymaster with credits. Users execute transactions with zero gas cost — the developer covers all fees.

starkfi config set-gasfree on

Under the hood, transactions are sent with feeMode: { type: "paymaster", gasToken } to the AVNU Paymaster endpoint.

Best for	How it works
Onboarding new users	Developer pays all gas from pre-funded credits
Demo environments	Users need zero token balance to transact

Gasless (User Pays in ERC-20)

Users pay gas in an ERC-20 token (ETH, USDC, USDT, DAI) instead of the default STRK. The Paymaster handles the token-to-gas conversion automatically.

starkfi config set-gas-token USDC

Under the hood, the SDK uses the v3 discriminated FeeMode union { type: "paymaster", gasToken: <tokenAddress> } to inject the gas token configuration.

Best for	How it works
Users without STRK	Pay gas in tokens they already hold
Stablecoin-heavy wallets	Use USDC/USDT/DAI for gas

Note: Setting a gas token clears gasfree mode, and vice versa. Use starkfi config list to verify your current mode.

Paymaster URLs

Network	URL
Mainnet	`https://starknet.paymaster.avnu.fi`
Sepolia	`https://sepolia.paymaster.avnu.fi`

StarkFi selects the correct URL automatically based on the configured network.

API Key (Optional)

If you have an AVNU Paymaster API key for authenticated access, set it as an environment variable:

export AVNU_PAYMASTER_API_KEY=your-api-key-here

StarkFi automatically includes this key in all paymaster requests when set.

Supported Gas Tokens

Token	Address (Mainnet)
ETH	`0x049d36570d...004dc7`
STRK	`0x04718f5a0f...7c938d` (default)
USDC	`0x033068f653...3b35fb`
USDT	`0x068f5c6a61...09c0fb8`
DAI	`0x05574eb6b8...ddf4ad`

How StarkFi Uses the Paymaster

StarkFi Command	Paymaster Role
`trade`, `send`, `batch`	Pays gas in configured token or via developer credits
`stake`, `unstake`, `rewards`	Same gas abstraction for staking operations
`lend-supply`, `lend-borrow`, etc.	Same gas abstraction for lending operations
`deploy`	Wallet deployment can also be gas-abstracted
`config set-gasfree on/off`	Toggle developer-sponsored mode
`config set-gas-token <token>`	Switch gas payment token
`config list`	View current fee mode and gas token