> For the complete documentation index, see [llms.txt](https://zootopia-finance.gitbook.io/zootopia-finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zootopia-finance.gitbook.io/zootopia-finance/financial-service/stableswap-amms.md).

# StableSwap AMMs

{% hint style="info" %}
​​Utilizing a *Zootopia Stableswap* model, users are able to:

Swap stablecoins at **hyper-efficient** exchange rates with **minimal slippage.** 

Earn a **sustainable and optimal yield** on their assets via **Muli-staking** pools.

We maximize capital utilization to fuel DeFi growth and adoption

——Zootopia Finance forked with Curve. For Details, check [CURVE WHITEPAPER.](https://curve.fi/files/crypto-pools-paper.pdf)
{% endhint %}

## Why provide stableswap service?

Although stable swaps seem like a simple enough concept, they're actually quite complex under the hood. Although complex, their efficiency has made stable swaps one of the most important tools in decentralized finance (DeFi) today.

<figure><img src="/files/6EANZliC942Hxwgr2V5H" alt=""><figcaption></figcaption></figure>

### **How Stableswap Invariant Pools Work**

Stableswap pools are the middle ground between constant product pools and constant price pools. A constant price pool is similar to a constant product pool, but uses a constant sum formula ***Rx***+***Ry***=**k**, resulting in a constant price **∆x** / **∆y** = 1.

The stableswap invariant algorithm uses an amplification parameter **A** that determines how close the stableswap curve should be to the constant product curve; an amplification value of 0 (*A = 0*) achieves results identical to the constant product pool algorithm; higher values of *A* push the curve closer to the constant price curve, resulting in lower slippage for exchange rates close to 1:1.

The formula for the stableswap invariant works by combining terms representing the constant product and constant sum formulas. It's using the constant **D** to represent the total number of tokens in the pool when token X and token Y have an equal price, and **A** represents the amplification parameter. The formula can be written as:

<figure><img src="/files/U4oBMdIGn7qhqPUweVKC" alt=""><figcaption></figcaption></figure>

#### Zootopia can gain the following advantages by developing a DEX exchange:

* Sustained and stable fee income.
* Provide liquidity for stablecoins trading pairs, **BNB-stkBNB** trading pairs, **ETH-womETH** trading pairs and other basic trading pairs, enriching the BSC network ecology.
* Provide liquidity for Zootopia's financial lending services and derivatives trading.

## Differences from other DEXs

Zootopia pool features unilateral liquidity provision where only one type of token is needed. No liquidity pair token-making is required from your cauldron, which makes liquidity provision impeccably flexible and scalable.

In addition to providing basic Base Reward income, Zootopia also allows users to use **Citizen Passport NFT for Boost**.