> ## Documentation Index > Fetch the complete documentation index at: https://developer.fin.com/llms.txt > Use this file to discover all available pages before exploring further. # Glossary > The core concepts behind the Fin.com API: customers, virtual accounts, beneficiaries, webhooks, coverage, and catalogue data. The terms below come up throughout this documentation. Each links to the guide that covers it in full. ## Customer The individuals and businesses you serve. Every customer is verified through Fin.com, with KYC for individuals and KYB for businesses, before they can hold an account or transact. Fin.com never contacts your customers directly. See [Onboarding individual customers](/guides/customers-and-compliance/onboarding-individuals) and [Onboarding business customers](/guides/customers-and-compliance/onboarding-businesses). ## Virtual account A set of bank details issued to one customer. Money paid into those details is converted and settled as stablecoin to a wallet address you nominate. A customer can hold one virtual account per currency and payment rail. See [Creating a virtual account](/guides/virtual-accounts/creating-a-virtual-account). ## Beneficiary A recipient your customer pays. A beneficiary belongs to one customer and has a single destination: a bank account, an e-wallet, or a crypto wallet. See [Beneficiary onboarding](/guides/beneficiaries/beneficiary-onboarding). ## Liquidation address The address issued for a bank or e-wallet beneficiary. Crypto sent to it is converted and paid out to that beneficiary in local currency, after fees. See [Creating your first beneficiary and payout](/guides/orchestration-dashboard/creating-your-first-beneficiary). ## Deposit instructions The bank details a virtual account exposes once it is active. Which fields are populated depends on the payment rail, so fields that do not apply come back empty. See [Receiving the first deposit](/guides/virtual-accounts/receiving-the-first-deposit). ## Developer fee Your own markup on a transaction. It can be a fixed amount, a percentage, or both, and both are applied together. It is deducted alongside conversion, so the settled amount is less than the amount sent. ## Counter party Whether your customer is paying themselves or someone else. First party means the customer is the beneficiary. Third party means they are paying a supplier, employee, or other recipient, which may bring additional compliance checks. See [Sender and receiver relationships](/guides/beneficiaries/sender-and-receiver-relationships). ## Beneficial ownership The funds in an account must belong to the account holder, even when paid in by a named third party such as a payment processor. Receiving funds that beneficially belong to someone who has not been onboarded is nesting, and is not permitted. See [Guidance on nested payments & onboarding](/guides/customers-and-compliance/nested-payments-and-onboarding). ## Webhook How Fin.com tells you something happened. Every event carries an envelope identifying the delivery and the resource it concerns, and every request is signed. See [Event structure](/guides/webhooks/event-structure) and [Verifying webhooks](/guides/webhooks/verifying-webhooks). ## RFI A request for information. Raised when more is needed to complete verification, whether from Fin.com to you, or from a banking partner to Fin.com. Nothing progresses until it is answered. See [SLAs for Compliance](/guides/customers-and-compliance/sla-for-compliance). ## Capabilities What a given customer is actually eligible for, by currency and rail. A customer can be approved without being eligible for every corridor, so check capabilities before assuming a flow is available. ## Coverage Which currencies and rails are available in each direction, and the risk classification applied per country of residence. See [Coverage & capabilities](/guides/coverage/coverage-and-capabilities) and [Supported rails and currencies](/guides/coverage/supported-rails-and-currencies). ## Catalogue Reference data the API expects in requests: occupations, transaction purposes, sources of funds, countries, and subdivision codes. Fetch these rather than hard-coding them. ## Rail The payment network money moves over. On the fiat side that means ACH, Fedwire, or SWIFT. On the crypto side it means the blockchain network, such as Ethereum or Polygon. ## Prefunding Holding a balance with Fin.com in advance so payouts can be settled without waiting for funds to arrive. Local currency payouts require it. See [Funding your balance](/guides/move-money/funding-your-balance).