# In-App Purchase Initialize Initializes the In-App Purchase SDK. Action available for the following operating systems: ![](/files/-MN57Y_zKMwAx_V80t5z) {% hint style="warning" %} Before calling any other In-App Purchase related action, you need to successfully call this action. {% endhint %} {% hint style="info" %} Kalipso implements the client side call of SDK functions provided by Google, Apple and Microsoft, but this is only a part of the entire In-App Purchase process.\ You need to be familiarized with the In-App purchase process and flows with each of these providers.\ Please read their documentation carefully, in order for you to understand what are the requirements on each of their portals for setting up In-App purchases and the products to be sold. Also to be aware of the security advises and practices you are advised to follow, like making purchases validation with your own server, and have the Kalipso Apps validating those purchases with your server to prevent frauds. {% endhint %} {% hint style="info" %} Also be aware of test procedures, that are different for the different providers. Read the providers documentaion on how to setup test accounts. * In Android, you can setup test Google accounts for using the In-App purchases in a test environment.\ At the time of writing this documentation, the information is available at this link:\ * With iOS it is possible to set up a Sandbox test account.\ At the time of writing this documentation, the information is available at this link:\ {% endhint %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://doc.sysdevmobile.com/kalipso5/developing/form/actions/actions-description/group-others/in-app-purchase-initialize.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.