> **Description:** Essential concepts, terminology, and definitions for understanding recurring payments, agreements, charges, and subscription lifecycle states.

# Concepts and terminology

Before proceeding with the documentation, we recommend familiarizing yourself with the key terminologies and concepts related to recurring payments.

## Payment agreement

A *payment agreement* is a mandate that a user reviews and approves in the app, authorizing the merchant to charge future payments using the payment source specified in the agreement.

### Types of payment agreements

* Fixed
* Variable
* Flexible

## Campaign

*Campaign* is a payment agreement feature suitable for merchants who will present a special offer to their users.
This feature can only be combined with payment agreements of type `fixed`.

### Types of campaigns

* Event
* Price
* Period

## Payment source

A *payment source* is the payment method such as Debit card, credit card, or account that the user has enrolled in the app.
The payment source that a user can choose while approving a payment agreement depends on the market and merchant configuration.

## Initial charge/up-front payment

The *initial charge* or *upfront payment* is the payment that the user is required to complete successfully when signing up for the payment agreement.
Only upon successful payment of the initial charge, will the agreement be deemed signed and active.

When there is no initial charge (i.e., initial charge amount is zero), the payment source is verified with a 0 NOK/DKK/EUR transaction.
Only on successful verification, the agreement is deemed signed and active.

## Charge

A *charge* is a payment request created by the merchant on the basis of a payment agreement.

### Types of charges

* Recurring charge with retries
* Recurring charge without retries
* Unscheduled charge

## Due (charge due date)

*Due*, the charge due date, is the date on which the charge created by the merchant will be processed by Vipps MobilePay.

## Profile sharing

*Profile sharing* is a feature that enables merchants to combine gathering user information and payment agreement sign up into a single user-friendly flow in the Vipps MobilePay app.

For more details, see [API guide: Profile sharing](https://developer.vippsmobilepay.com/docs/APIs/recurring-api/recurring-api-guide.md#profile-sharing).

> **Full site overview:** For every page in this documentation, read [https://developer.vippsmobilepay.com/llms.txt](https://developer.vippsmobilepay.com/llms.txt).