> For the complete documentation index, see [llms.txt](https://docs.thndr.io/integration/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.thndr.io/integration/launch-game/custom.md).

# Custom

The [**THNDR SDK**](https://github.com/THNDRGAMES/clinch-sdk) enables secure communication between a parent website and an embedded game. It provides an easy way to handle operations like token authentication, and balance retrieval, facilitating seamless interactions between the two contexts. The SDK uses the `postMessage` API to ensure secure message passing between the parent and the game.