> Portal Navigation: > > - Append `.md` to any URL under `https://dev.wix.com/docs/` to get its markdown version. > - Pages are either content pages (article or reference text) or menu pages (a list of links to child pages). > - To get a menu page, truncate any URL to a parent path and append `.md` (e.g. `https://dev.wix.com/docs/sdk.md`, `https://dev.wix.com/docs/sdk/core-modules.md`). > - Top-level index of all portals: https://dev.wix.com/docs/llms.txt > - Full concatenated docs: https://dev.wix.com/docs/llms-full.txt ## Resource: wix-payment-provider-backend ## Article: Introduction ## Article Link: https://dev.wix.com/docs/velo/apis/wix-payment-provider-backend/introduction.md ## Article Content: # Introduction
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The Payment Provider Backend API allows you to report transaction and refund events when implementing the Payment Provider Custom Extension. Use it together with the [Payment Provider SPI](https://www.wix.com/velo/reference/spis/wix-payments/payment-provider/introduction). Learn more about implementing a [Payment Provider Custom Extension](https://support.wix.com/en/article/velo-tutorial-payment-provider-custom-extension-beta).