# Core API

<mark style="color:blue;">`GET`</mark> `https://api2.chainge.finance/fun/getVault`

#### Query Parameters

| Name                                     | Type   | Description  |
| ---------------------------------------- | ------ | ------------ |
| ticker<mark style="color:red;">\*</mark> | String | krc20 ticker |

{% tabs %}
{% tab title="200:OK" %}

```json
{
    "code": 0,
    "msg": "success",
    "data": {
        "vault": "kaspa:qp6fny54gn7ydnxaltmmezc60qnleksxu6ctvtjch2dlvkvg8pak6rh33st6w"
    }
}
```

{% endtab %}
{% endtabs %}

<mark style="color:blue;">`GET`</mark> `https://api2.chainge.finance/fun/quote`

#### Query Parameters

| Name                                         | Type   | Description                               |
| -------------------------------------------- | ------ | ----------------------------------------- |
| fromTicker<mark style="color:red;">\*</mark> | String | krc20 ticker                              |
| toTicker<mark style="color:red;">\*</mark>   | String | krc20 ticker                              |
| fromAmount<mark style="color:red;">\*</mark> | String | BigNumber String. ex: 10 kas , 1000000000 |

{% tabs %}
{% tab title="200:OK" %}

```postman_json
{
    "code": 0,
    "msg": "success",
    "data": {
        "amountOut": "75553316920000",
        "amountOutUsd": "1.14",
        "userAmountOut": "38702849054762",
        "serviceFee": "2266599507600",
        "gasFee": "34583868357638",
        "serviceFeeRate": "3%",
        "priceImpact": "0.61%",
        "slippage": "5%"
    }
}
```

{% endtab %}
{% endtabs %}

<mark style="color:blue;">`POST`</mark> `https://api2.chainge.finance/fun/submitSwap`

#### Query Parameters

| Name                                          | Type   | Description                               |
| --------------------------------------------- | ------ | ----------------------------------------- |
| channel<mark style="color:red;">\*</mark>     | String | Unique KEY. ex: knot                      |
| certHash<mark style="color:red;">\*</mark>    | String | Transaction hash                          |
| fromTicker<mark style="color:red;">\*</mark>  | String | krc20 ticker                              |
| fromAmount<mark style="color:red;">\*</mark>  | String | BigNumber String. ex: 10 kas , 1000000000 |
| toTicker<mark style="color:red;">\*</mark>    | String | krc20 ticker                              |
| toAmount<mark style="color:red;">\*</mark>    | String | BigNumber String. ex: 10 kas , 1000000000 |
| toAmountMin<mark style="color:red;">\*</mark> | String | BigNumber String.                         |

**Headers Parameters**

| Name                                        | Type   | Description      |
| ------------------------------------------- | ------ | ---------------- |
| Address<mark style="color:red;">\*</mark>   | String | User address     |
| PublicKey<mark style="color:red;">\*</mark> | String | User publicKey   |
| Chain<mark style="color:red;">\*</mark>     | String | KAS              |
| Signature<mark style="color:red;">\*</mark> | String | Verify signature |

{% tabs %}
{% tab title="200:OK" %}

```
{
    "code": 0,
    "msg": "success",
    "data": {
        "id": "2030000000003",
    }
}
```

{% endtab %}
{% endtabs %}

<mark style="color:blue;">`GET`</mark> `https://api2.chainge.finance/fun/checkSwap`

#### Query Parameters

| Name                                 | Type   | Description                 |
| ------------------------------------ | ------ | --------------------------- |
| id<mark style="color:red;">\*</mark> | String | submitSwap result, order id |

{% tabs %}
{% tab title="200:OK" %}

```json
{
    "code": 0,
    "msg": "success",
    "data": {
        "status": "Succeeded",
        "hash": "dd2a4f0553f38eec8cad797965c2522bb59dd5308ce2a893ec15adfeb82aa19d",
        "since": 1736935562
    }
}
```

{% endtab %}
{% endtabs %}

{% hint style="info" %}
status: &#x20;

***Unknown, Refunding, Pending*** //all regarded as pending&#x20;

***Succeeded*** //order executed successfully&#x20;

***Dropped*** //order dropped for any reasons, manual refund is needed&#x20;

***Refunded*** //order cannot proceed for any reasons, system refunded automatically
{% endhint %}

example:&#x20;

This example is for demonstration purposes only.

```javascript
import BigNumber from 'bignumber.js';
import { formatUnits, hexlify, parseUnits, toUtf8Bytes } from 'ethers'

const fromAddress = 'kaspa:qzg4g46sd3hnax9fnjqdc2jfljs39f9ng00ntfhdz28rfwyc8adzuksnutgrq'
const publicKey = '03915457506c6f3e98a99c80dc2a49fca112a4b343df35a6ed128e34b8983f5a2e'
const wallet = {} // The kasWare wallet object.


const fromAmount = '10'
const fromAmountSwap = parseUnits(fromAmount, 8).toString(); // The decimals for KRC20 tokens are all set to 8.
let customSlippage = '5' // percentage format, ex: 5%
let toExpectAmount = ''

let toAmountSwap = ''
let toAmountMinSwap = ''
const fnGetQuote = async () => {
    const quoteParams = {
        fromTicker: "KAS",
        toTicker: "RATS",
        fromAmount: fromAmountSwap
    }

    // quote 
    const response = await fetch(`https://api2.chainge.finance/fun/quote?fromTicker=${quoteParams.fromTicker}&toTicker=${quoteParams.toTicker}&fromAmount=${quoteParams.fromAmount}`)
    const quoteResult = await response.json()
    if(quoteResult.code !== 0) return
    let { amountOut, serviceFee, gasFee, slippage } = quoteResult.data
    // slippage: 5%
    slippage = slippage.replace('%', '') // '5'

    const receiveAmount = BigInt(amountOut) - BigInt(serviceFee) - BigInt(gasFee)
    if(receiveAmount <= BigInt(0)) {
        // The current quote amount cannot cover the fees. Please enter a larger amount.
        return
    }

    // Calculate the value the user should receive. 
    const receiveAmountHr = formatUnits(receiveAmount, 8)


    // Computed minimum, After calculating the minimum value, we need to convert it to the decimals of the target chain.
    // The slippage here is in percentage format. 
    // The slippage returned by this interface is our recommended value, but you can set your own slippage.
    const tempSlippage = customSlippage || slippage
    const miniAmountHr = BigNumber(receiveAmountHr).multipliedBy(BigNumber((1 - (tempSlippage * 0.01)))).toFixed(8, BigNumber.ROUND_DOWN)
    const miniAmount = parseUnits(miniAmount, 8).toString()
    
    toAmountSwap = receiveAmount
    toAmountMinSwap = miniAmount
}

const fnSubmitSwap = async (tradeHash) => {
    const params = {
        fromTicker: "KAS",
        fromAmount: fromAmountSwap,
        toTicker: 'RATS',    
        toAmount: toAmountSwap,
        toAmountMin: toAmountMinSwap,
        certHash: tradeHash,
        channel: "knot",
    };
    
    let raw = `${params.channel}_${params.certHash}_${params.fromTicker}_${params.fromAmount}_${params.toTicker}_${params.toAmount}_${params.toAmountMin}`

    // Use the signMessage method of the kasWare wallet to sign a string.
    // let signature = wallet.signMessage(raw)
    let signature = ''

    const header = {
        Address: fromAddress,
        PublicKey: publicKey,
        Chain: 'KAS',
        Signature: signature
    }

    const response = await fetch('https://api2.chainge.finance/fun/submitSwap', {
        method: "POST",
        headers: {
             "Content-Type": "application/json",
             ...header
        },
        body: JSON.stringify(params)
    })
    const result = await response.json()
}

const fnGetMinterAddr = async () => {
    const response = await fetch('https://api2.chainge.finance/fun/getVault?ticker=KAS')
    const result = await response.json()
    return result.data.vault
}


const fnCore = async () => {
    // step 1: quote 
    await fnGetQuote()
    
    // step 2: get minter address
    const minterAddr = await fnGetMinterAddr()

    // step 3: Send transaction 
    // You need to initiate a transaction to our minter through the wallet, and obtain the hash. This hash will be the transaction hash.
    // const txHash = await wallet.signKRC20Transaction()
    const txHash = ''

    // step 4: submitOrder
    await fnSubmitSwap(txHash)
}

fnCore()
```


---

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