Sponsoring Gas with Paymaster

With our Paymaster service, we provide granular, API-driven tools to precisely manage your sponsorship strategy and budget.

Note

To update your gas sponsorship settings, please contact us.

1. Granular Sponsorship Controls You have fine-grained control over which on-chain activities you sponsor. - Sponsor Specific Contract Functions: Whitelist transactions based on the specific function being called (via its function selector). - Example: A DeFi protocol could sponsor the deposit function but not the withdraw function. - Sponsor A Specific Contract: Whitelist all interactions with a particular smart contract address. - Support for Atomic Batch Transactions: The service can process a UserOperation containing multiple actions. The entire batch is treated as a single, atomic unit; if any one of the bundled actions fails the policy validation, the entire transaction is rejected, preventing partial execution and unintended gas spending.
2. ERC-20 Paymaster Support
   • For user operations that do not qualify for sponsorship, users can opt to pay gas fees using ERC-20 tokens, including MOCA, USDT, USDC, EURe, and others. For a complete list of supported tokens, please contact us.
3. Powerful Policy & Budget Management You can define comprehensive policies to govern their sponsorship activities and control costs. - Multi-Chain Policy Configuration: Define and manage entirely separate sponsorship policies and allowlists for each supported blockchain (e.g., Ethereum, Polygon, Base). - Set Granular Spending Limits: Establish robust budgets with different scopes and reset intervals (daily, weekly, monthly): - Global Limit: A total budget for the entire policy. - Per-User Limit: A spending cap for each individual user. - Control Transaction Costs: Set a maximum gas cost (maxGasCost) you are willing to sponsor for a single UserOperation to protect against volatile or unexpectedly expensive transactions. - Time-based Policy Activation: Schedule policies to automatically activate and deactivate at specific start and end times, ideal for limited-time promotions or campaigns.

How It Works: The Sponsorship Flow

The sponsorship process is a high-speed, automated workflow compliant with the ERC-4337 standard for Account Abstraction. It functions as the core logic for the pm_sponsorUserOperation RPC method.

1. Sponsorship Request: The flow begins when a user action in a partner application, via our SDK, generates a UserOperation. The SDK then calls the pm_sponsorUserOperation endpoint to determine sponsorship eligibility.
2. Webhook to Paymaster: our bundler provider receives this request and forwards it as a webhook to our Paymaster Service.
3. Policy Validation: Our Paymaster Service validates the incoming UserOperation against the partner's configured Sponsorship Policy. This is a real-time check of all conditions, including spending limits, gas limits, and whether the transaction's target address and function selector are on the partner's Allowlist.
4. Sponsorship Decision: Based on the validation result, our service responds:
   • On Success: The Paymaster cryptographically signs the UserOperation and returns the paymasterAndData field. This serves as the on-chain proof of sponsorship, allowing the transaction to be bundled and executed.
   • On Failure: The service returns an error, rejecting the sponsorship request. Our SDK is designed to handle this failure gracefully, falling back to a standard transaction flow where the user pays the gas fee themselves.