# yi

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Yi Token by Crate Protocol: the primitive for auto-compounding single token staking pools.

## About

**Yi** is a Solana primitive for building single-sided, auto-compounded stake pools. It allows
projects to launch *Yi Tokens*, which are tokens convertible to and from an underlying token.

Some example use cases include:

- *Governance token staking.* Protocols may want their governance token to be staked, where fees are converted into the governance token. An example of this is the XSUSHI pool in Sushiswap.
- *Interest-bearing derivatives.* A protocol may collect revenue in a token that it wants users to stake, so it may pay fees out by compounding that token. An example of this is Anchor UST.

## Usage

First, create a Yi Token by invoking the [`yi::create_yi_token`] instruction. Then, anyone may stake
tokens into the pool via [`yi::stake`].

To send auto-compounded rewards to the pool, deposit tokens to the [`YiToken::underlying_tokens`] token account.
This will increase the conversion rate of Yi Tokens to underlying tokens.

To exit the pool, invoke [`yi::unstake`].

### Fees

Yi Tokens may take stake or unstake fees. These fees cannot be changed after the construction of the Yi Token. Fees get distributed
to stakers within the Yi Token pool.

## Packages

- NPM Package: [`@crateprotocol/yi`](https://www.npmjs.com/package/@crateprotocol/yi)
- Crates.io: [`yi`](https://crates.io/crates/yi)

## Address

The Yi program is deployed on `mainnet-beta` and `devnet` at [`YiiTopEnX2vyoWdXuG45ovDFYZars4XZ4w6td6RVTFm`](https://anchor.so/programs/YiiTopEnX2vyoWdXuG45ovDFYZars4XZ4w6td6RVTFm).

## License

Yi Token by Crate Protocol is licensed under the Affero General Public License, version 3.0.