> ## Documentation Index
> Fetch the complete documentation index at: https://developers.stellar.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Quote

> The [SEP-38] standard defines a way for anchors to provide quotes for the exchange of an off-chain asset and a different on-chain asset, and vice versa.

> [!NOTE]
>
> This guide is available on four different programming languages: Typescript, Kotlin, Flutter (Dart) and Swift. You can change the shown version on each page via the buttons above.

> [!CAUTION]
>
> **Important**
>
> Documentation for this language is currently work in progress. Some of information may not be applicable for this language, or missing. Code samples may be incomplete.

> [!WARNING]
>
> **Important**
>
> Documentation for Kotlin is currently work in progress. Some of information may not be applicable for Kotlin, or missing. Code samples may be incomplete.

The [SEP-38] standard defines a way for anchors to provide quotes for the exchange of an off-chain asset and a different on-chain asset, and vice versa. Quotes may be [indicative](https://www.investopedia.com/terms/i/indicativequote.asp) or [firm](https://www.investopedia.com/terms/f/firmquote.asp) ones. When either is used is explained in the sections below.

## Creating SEP-38 Object

Let's start with creating a sep38 object, which we'll use for all SEP-38 interactions. Authentication is optional for these requests, and depends on the anchor implementation. For our example we will include it.

Authentication is done using [Sep-10], and we add the authentication token to the sep38 object.

**TypeScript**

```typescript theme={"theme":{"light":"github-light","dark":"github-dark"}}
const accountKp = ... // our account keypair

const auth = await anchor.sep10();
const authToken = await auth.authenticate({ accountKp });
const sep38 = anchor.sep38(authToken);
```

**Flutter**

```dart theme={"theme":{"light":"github-light","dark":"github-dark"}}
var accountKp = ... // our account keypair

var auth = await anchor.sep10();
var authToken = await auth.authenticate(accountKp);
var sep38 = anchor.sep38(authToken: authToken);
```

**Swift**

```swift theme={"theme":{"light":"github-light","dark":"github-dark"}}
let accountKp = ... // our account keypair

let sep10 = try await anchor.sep10
let authToken = try await sep10.authenticate(userKeyPair: accountKp)
let sep38 = try await anchor.sep38(authToken: authToken)
```

## Get Anchor Information

First, let's get information about the anchor's support for [SEP-38]. The response gives what stellar on-chain assets and off-chain assets are available for trading.

**TypeScript**

```typescript theme={"theme":{"light":"github-light","dark":"github-dark"}}
const resp = await sep38.info();
```

**Flutter**

```dart theme={"theme":{"light":"github-light","dark":"github-dark"}}
var resp = await sep38.info();
```

**Swift**

```swift theme={"theme":{"light":"github-light","dark":"github-dark"}}
let resp = try await sep38.info
```

For example a response will look like this. The asset identifiers are described below in [Asset Identification Format](#asset-identification-format).

```
{
  assets: [
    {
      asset: 'stellar:SRT:GCDNJUBQSX7AJWLJACMJ7I4BC3Z47BQUTMHEICZLE6MU4KQBRYG5JY6B'
    },
    {
      asset: 'iso4217:USD',
      country_codes: [Array],
      sell_delivery_methods: [Array],
      buy_delivery_methods: [Array]
    }
  ]
}
```

## Asset Identification Format

Before calling other endpoints we should understand the scheme used to identify assets in this protocol. The following format is used:

```
<scheme>:<identifer>
```

The currently accepted scheme values are `stellar` for Stellar assets, and `iso4217` for fiat currencies.

For example to identify USDC on Stellar we would use:

```
stellar:USDC:GA5ZSEJYB37JRC5AVCIA5MOP4RHTM335X2KGX3IHOJAPP5RE34K4KZVN
```

And to identify fiat USD we would use:

```
iso4217:USD
```

Further explanation can be found in [SEP-38 specification](https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0038.md#asset-identification-format).

## Get Prices

Now let's get [indicative](https://www.investopedia.com/terms/i/indicativequote.asp) prices from the anchor in exchange for a given asset. This is an indicative price. The actual price will be calculated at conversion time once the Anchor receives the funds from a user.

In our example we're getting prices for selling 5 fiat USD.

**TypeScript**

```typescript theme={"theme":{"light":"github-light","dark":"github-dark"}}
const resp = await sep38.prices({
  sell_asset: "iso4217:USD",
  sell_amount: "5",
});
```

**Flutter**

```dart theme={"theme":{"light":"github-light","dark":"github-dark"}}
var resp = await sep38.prices(
  sellAsset: "iso4217:USD",
  sellAmount: "5",
);
```

**Swift**

```swift theme={"theme":{"light":"github-light","dark":"github-dark"}}
let response = try await sep38.prices(sellAsset: "iso4217:USD",
                                      sellAmount: "5")
```

The response gives the asset prices for exchanging the requested sell asset. For example, a response look like this:

```
{
  "buy_assets": [
    {
      "asset": "stellar:USDC:GA5ZSEJYB37JRC5AVCIA5MOP4RHTM335X2KGX3IHOJAPP5RE34K4KZVN",
      "price": "5.42",
      "decimals": 7
    }
  ]
}
```

## Get Price

Next, let's get an [indicative](https://www.investopedia.com/terms/i/indicativequote.asp) price for a certain pair.

Once again this is an indicative value. The actual price will be calculated at conversion time once the Anchor receives the funds from a User.

Either a `sellAmount` or `buyAmount` value must be given, but not both. And `context` refers to what Stellar SEP context this will be used for (ie. `sep6`, `sep24`, or `sep31`).

**TypeScript**

```typescript theme={"theme":{"light":"github-light","dark":"github-dark"}}
const resp = await sep38.price({
  sellAsset: "iso4217:USD",
  buyAsset:
    "stellar:SRT:GCDNJUBQSX7AJWLJACMJ7I4BC3Z47BQUTMHEICZLE6MU4KQBRYG5JY6B",
  sellAmount: "5",
  context: "sep6",
});
```

**Flutter**

```dart theme={"theme":{"light":"github-light","dark":"github-dark"}}
var resp = await sep38.price(
  sellAsset: "iso4217:USD",
  buyAsset:
    "stellar:SRT:GCDNJUBQSX7AJWLJACMJ7I4BC3Z47BQUTMHEICZLE6MU4KQBRYG5JY6B",
  sellAmount: "5",
  context: "sep6",
);
```

**Swift**

```swift theme={"theme":{"light":"github-light","dark":"github-dark"}}
let resp = try await sep38.price(
    context: "sep6",
    sellAsset: "iso4217:USD",
    buyAsset: "stellar:SRT:GCDNJUBQSX7AJWLJACMJ7I4BC3Z47BQUTMHEICZLE6MU4KQBRYG5JY6B",
    sellAmount: "5")
```

The response gives information for exchanging these assets. For example, a response will look like this:

```
{ price: '1.18', sell_amount: '5.00', buy_amount: '4.24' }
```

## Post Quote

Now let's get a [firm](https://www.investopedia.com/terms/f/firmquote.asp) quote from the anchor. As opposed to the earlier endpoints, this quote is stored by the anchor for a certain period of time. We will show how we can grab the quote again later.

The request body is similar to the `.price()` call we made earlier.

**TypeScript**

```typescript theme={"theme":{"light":"github-light","dark":"github-dark"}}
const requestResp = await sep38.requestQuote({
  sell_asset: "iso4217:USD",
  buy_asset:
    "stellar:SRT:GCDNJUBQSX7AJWLJACMJ7I4BC3Z47BQUTMHEICZLE6MU4KQBRYG5JY6B",
  sell_amount: "5",
  context: "sep6",
});
```

**Flutter**

```dart theme={"theme":{"light":"github-light","dark":"github-dark"}}
var requestResp = await sep38.requestQuote(
  sellAsset: "iso4217:USD",
  buyAsset:
    "stellar:SRT:GCDNJUBQSX7AJWLJACMJ7I4BC3Z47BQUTMHEICZLE6MU4KQBRYG5JY6B",
  sellAmount: "5",
  context: "sep6",
);
```

**Swift**

```swift theme={"theme":{"light":"github-light","dark":"github-dark"}}
let resp = try await sep38.requestQuote(
    context: "sep6",
    sellAsset: "iso4217:USD",
    buyAsset: "stellar:SRT:GCDNJUBQSX7AJWLJACMJ7I4BC3Z47BQUTMHEICZLE6MU4KQBRYG5JY6B",
    sellAmount: "5")
```

However now the response gives an `id` that we can use to identify the quote. The `expires_at` field tells us how long the anchor will wait to receive funds for this quote.

An example response looks like this:

```
{
  id: '019417b3-91ce-473a-929f-15e19470733a',
  price: '0.81',
  expires_at: '2024-01-03T20:34:48.190481Z',
  sell_asset: 'iso4217:USD',
  buy_asset: 'stellar:SRT:GCDNJUBQSX7AJWLJACMJ7I4BC3Z47BQUTMHEICZLE6MU4KQBRYG5JY6B',
  sell_amount: '5.00',
  buy_amount: '6.17'
}
```

## Get Quote

Now let's get the previously requested quote. To do that we use the `id` from the `.requestQuote()` response.

**TypeScript**

```typescript theme={"theme":{"light":"github-light","dark":"github-dark"}}
const quoteId = requestResp.id;
const getResp = await sep38.getQuote(quoteId);
```

**Flutter**

```dart theme={"theme":{"light":"github-light","dark":"github-dark"}}
var quoteId = requestResp.id;
var getResp = await sep38.getQuote(quoteId);
```

**Swift**

```swift theme={"theme":{"light":"github-light","dark":"github-dark"}}
let quoteId = requestResp.id
let getResp = try await sep38.getQuote(quoteId: quoteId)
```

The response should match the one given from `.requestQuote()` we made earlier.

[sep-10]: https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0010.md

[sep-38]: https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0038.md