# Verifying Paymaster

Pimlico's Verifying Paymaster is a combination of an API and an on-chain smart contract that allows you to sponsor gas fees for your users. By calling our API, you get back a signature that will be accepted by our smart contract and will pay for the gas fees of your users.

## Tutorials

Learning-oriented lessons that take you through a series of steps to complete a project. Most useful when you want to get started with Pimlico. They all involve the Alto Bundler.

* [Tutorial 1](/references/permissionless/tutorial/tutorial-1) leverages the Verifying Paymaster to sponsor the gas fees for a User Operation.

## References

References provide specific technical descriptions. They are most useful when you need detailed information about Pimlico's APIs.

* The [supported chains page](/guides/supported-chains) for the verifying paymaster explains the chains and networks that are supported and the API endpoints you can use to interact with it.