# Getting started

Before starting work, make sure that you have released the api key [Getting API key](https://doc.heleket.com/general/getting-api-keys.md)

## Selecting the type of integration

There are 2 types of integration

1.  [**Invoice**](https://doc.heleket.com/methods/payments/creating-invoice.md)

    This payment method is suitable for paying for goods with a specific amount.

    You can specify the currency, then the payer can select the cryptocurrency and network on the payment page.You can also specify the crypto-currency and network immediately, then a crypto-currency address will be generated and you can give it to the client.

    Once the client has paid, you will receive a notification - a webhook, which indicates the status, the payment amount and hash, as well as additional data (more details - [**Link**](https://doc.heleket.com/methods/payments/webhook.md) )

    If the client didn’t pay, you will receive the **cancel** status.  
    If the client sent the exact amount, you will receive a **paid** status.  
    If the client sent a lower amount, you will receive the **wrong\_amount** status.  
    If the client sent a higher amount, you will receive the **paid\_over** status.

    To allow the client to pay the rest, pass the parameter **is\_payment\_multiple = true**

    On the payment page, the client will be notified that there is a surcharge to be paid. If the client doesn't pay the rest of an amount, you will receive a webhook with the **wrong\_amount** status, when the invoice expires.

2.  [**Static wallet**](https://doc.heleket.com/methods/payments/creating-static.md)

    _Suitable for balance top-up_

    You can create a static address in a specific currency and network. The address will be attached to the **order\_id**

    All transactions sent to this address will be credited regardless of the amount.