# Glossary

### Merchant

An individual or organization with access to Inqud's API and authorized to use the On-Ramp API.

### User

Or end user (interchangeably), a customer of a merchant who will pay for the merchant's services or goods.

### Project

A core entity of on-ramp, linking all operations within its scope. Merchants can create checkouts for users, setup notification about its status.

### Checkout

An invoice with a specified amount, which can be in any currency. Users can open checkout page and perform a payment. Inqud handles the conversion between the checkout currency and the user-pay currency. At the moment merchant receives funds in USDC.\
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Checkouts outs can be of two types: FIXED\_PRICE (with a specified amount) and NO\_PRICE (without a specified amount). 

### Payment

A payment refers to an actual incoming transaction processed by Inqud, which is visible on the Wallets page in the user's Cabinet.

### Callback/Webhook

A notification sent by the Inqud system to the merchant's backend to propagate information about  checkouts. Callbacks enable real-time updates on payment status and other transaction-related events.