> For the complete documentation index, see [llms.txt](https://wllxpay.gitbook.io/wllxpay-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wllxpay.gitbook.io/wllxpay-documentation/api-documentation/callbacks.md).

# Callbacks

Asynchronous payments are very popular with cryptocurrencies. In such deposit flow you have to generate an address and pass it to your client. This will be his deposit address which he will be reusing during his lifetime with you. In such payment flow we will notify you about any incoming payments with callbacks.

Owner of the merchant can set up callback URL manually in merchant's settings, and upon processing payments, WllxPay will send you notifications in JSON format with all required information about transaction such as amount and status.

Callback retry schedule:\
\
1, 5, 10, 15, 20, 30, 60, 90, 120, 150, 180, 210, 240 minutes.

[API V1 callbacks specification](https://app.gitbook.com/@wllxpay/s/wllxpay-documentation/api-documentation/v1#callbacks)

[API V2 callbacks specification](https://app.gitbook.com/@wllxpay/s/wllxpay-documentation/~/drafts/-LugMVkGGY8DgR_5ZHhl/api-documentation/v2)