> For the complete documentation index, see [llms.txt](https://docs.cros.world/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cros.world/sdk-and-apis/open-apis.md). # Open APIs ## Ad Bidding APIs Cros provides bidding APIs for third-party demand partners to compete for the ad-inventory across games in a set of auctions. The API will also include reporting, traffic and billing information in future. The bidding APIs collect bid responses from third party demand partners which are channeled back to the auction engine. Based on the ad-inventory and other parameters, an appropriate auction format is chosen, and a unified auction is run for all the bid responses to determine the most efficient allocation of inventory. Ad Bidding APIs are designed keeping IAB certified version of the OpenRTB spec in mind making it easy to integrate with DSPs compliant with OpenRTB specification. ## Ad Serve APIs All deployed Cros ad-assets on different game platforms fetch the advertisements through an ad-serving API. This API is bundled in different configurations based on ad-media, ad-packaging for a native experience in a game and other parameters. The Ad server APIs make it possible for native experiences to be built by each game or gaming platform such that Cros Ad platform serves the most appropriate ad-media based on environment and user context while the display and interaction is controlled by the game - which could be through a device or any other medium. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## 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, and the optional `goal` query parameter: ``` GET https://docs.cros.world/sdk-and-apis/open-apis.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.