# Developing a client contract
A client is a contract that makes requests to providers using the Airnode.sol contract that implements the protocol. A client is endorsed by a requester, which means that it can specify its request to be fulfilled by the respective requester's designated wallet.
The Airnode protocol is designed to be flexible, and is meant to serve a variety of use cases. The first step a requester needs to take is to develop and deploy such a client contract.
# Endorsing your contract
Assuming you have already created a requester, you should endorse the client contract so that it can make requests.
You can use @api3/airnode-admin (opens new window) to endorse client contracts.
Endorsing a client contract means it can make requests that will be fulfilled by the designated wallet associated with your requester record.
You can use @api3/airnode-admin (opens new window) to derive your designated wallet and fund it so that the provider you have made requests to can fulfill your requests.