> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hub2.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Glossary

> Definition of useful terms used in HUB2's payment platform

## Collection Account

Account used for payments.

## Transfer Account

Account used for transfers.

## IRT Transfer Account

Account used for IRT.

## IRT (International Remittance Transfers)

The cross-border transfer of funds from one person to another.

## Payment

A payment (or PAY-IN) is a financial transaction in which money is moved from the user's account to the merchant's collection account.

## Transaction  polling

A method of periodically retrieving the status of a transaction by regularly querying an API for updates. [Polling vs. Webhooks](https://blog.bytebytego.com/i/141963246/polling-vs-webhooks)

## Balance

Difference between total debit transactions (transfers/pay-outs, withdrawals, fees) and total credit transactions (payments collected/pay-ins, deposits). The difference cannot be negative. Consequently, the balance is a credit balance.

## Transfer

A transfer (or PAY-OUT) is a financial transaction in which money is moved from the merchant's transfer account to the user's account.

## Webhook

Sending notifications to the merchant when specific events occur. [Polling vs. Webhooks](https://blog.bytebytego.com/i/141963246/polling-vs-webhooks)

## IPN

Instant Payment Notification. Webhooks sent by providers to HUB2.

## KYB

Know Your Business - A declaration in which an aggregator merchant provides informations about a merchant he aggregates. This prior declaration is necessary to use the [bank collection feature](/integration/en/other_products/bank_collection)

## KYB transaction

Declaration made by a merchant-aggregator when making a bank transfer to HUB2 to refill its account.
This information enables HUB2's teams to check the conformity of the transaction and validate it.

## KYC

Know Your Customer - A process for verifying the identity of a company's customers.

## Submerchant

An account linked to a PSP or Fintech Merchant account that is granted a unique ID to process transactions. This structure ensures compliance with regulatory requirements.