> For the complete documentation index, see [llms.txt](https://sandcastle.gitbook.io/sand-castle-finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sandcastle.gitbook.io/sand-castle-finance/lending/more-customization.md).

# More Customization

## Token Holders

A token holder is a seperate address that essentially holds onto your tokens and is called whenever a position is created. This can be implemented with any existing yield platform to boost earnings.

**Example:** A user can have a token holder that places their funds in Aave to passively earn yield until a user borrows their tokens. This can help mitigate idle liquidity within the platform.

## Interest Rate Routers

An interest rate router is a seperate address that can be used to add in other mechanics to determine the interest of borrowing tokens. 

**Example:** A interest rate router could be set to use chainlink or another system.