> For the complete documentation index, see [llms.txt](https://docs.galaxypay.vn/upc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.galaxypay.vn/upc/payment-gateway/api-specification/ipn-and-callback.md).

# IPN & CALLBACK

- [Result & IPN Callback](https://docs.galaxypay.vn/upc/payment-gateway/api-specification/ipn-and-callback/result-and-ipn-callback.md)
- [Cancel Callback](https://docs.galaxypay.vn/upc/payment-gateway/api-specification/ipn-and-callback/cancel-callback.md)