> For the complete documentation index, see [llms.txt](https://xpansionchain-1.gitbook.io/xpansionchain/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://xpansionchain-1.gitbook.io/xpansionchain/advanced-guides/nft-primary-sale-card-checkout/set-up-required-endpoints.md).

# Set up required endpoints

## Set up required endpoints

FEATURE FOR MANAGED PARTNERS ONLY

This is a feature intended for managed partners. If you are not a managed partner and would like to become one, please reach out to us on our <mark style="color:blue;">#dev-discussion channel</mark> on Discord.

If you are a managed partner, your partner success manager needs to set up a commercial partnership with MoonPay for you. Please reach out to them to facilitate this.

In order to <mark style="color:blue;">implement</mark> this NFT primary sale card checkout feature, you need to complete the following:

1. Establish a commercial partnership with MoonPay (your partner success manager will facilitate this for you)
2. <mark style="color:blue;">Set up and register with XpansionChain with the required endpoints</mark>

### How to set up and register endpoints[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#how-to-set-up-and-register-endpoints) <a href="#how-to-set-up-and-register-endpoints" id="how-to-set-up-and-register-endpoints"></a>

💡STEPS:

1. <mark style="color:blue;">Create required endpoints</mark>
2. <mark style="color:blue;">Register with XpansionChain using created endpoints</mark>
3. <mark style="color:blue;">Validate the</mark> <mark style="color:blue;"></mark><mark style="color:blue;">`IMX-Signature`</mark>

#### 1. Create endpoints[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#1-create-endpoints) <a href="#id-1-create-endpoints" id="id-1-create-endpoints"></a>

You are required to provide the following endpoints:

1. <mark style="color:blue;">Trigger the mint</mark>: An endpoint to mint the asset once payment has been confirmed with MoonPay
2. <mark style="color:blue;">Get asset info</mark>: An endpoint to get information about the minted asset and render the checkout

#### Triggering the mint endpoint[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#triggering-the-mint-endpoint) <a href="#triggering-the-mint-endpoint" id="triggering-the-mint-endpoint"></a>

**Headers required:**[**​**](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#headers-required)

| Name                                                                    | Description                                                     |
| ----------------------------------------------------------------------- | --------------------------------------------------------------- |
| `IMX-Signature` - <mark style="color:blue;">How to validate this</mark> | Signature to confirm that the request was made by XpansionChain |
| `IMX-Timestamp` - <mark style="color:blue;">How to generate this</mark> | Timestamp header to validate `IMX-Signature`                    |

**Request body:**[**​**](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#request-body)

| Property                  | Type          | Description                                                                                  |
| ------------------------- | ------------- | -------------------------------------------------------------------------------------------- |
| `offer_id`                | String        | The ID of the offer provided for the NFT to be minted                                        |
| `contract_address`        | String        | Smart contract address of the NFT                                                            |
| `user`                    | String        | User that the NFT will be minted for (will become the NFT's owner)                           |
| `wallet_address`          | String        | Wallet address that will receive the payment, in crypto (from MoonPay), for the minted NFT   |
| `external_transaction_id` | String (UUID) | Unique XpansionChaintransaction ID that can be used to get information about the transaction |

**Response:**[**​**](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#response)

| Property           | Type    | Descrtiption                                                                      |
| ------------------ | ------- | --------------------------------------------------------------------------------- |
| `contract_address` | String  | Smart contract address of the NFT                                                 |
| `token_id`         | String  | Token ID (as specified by the NFT smart contract) of the minted asset             |
| `tx_id`            | Integer | Minting transaction ID - see <mark style="color:blue;">mintTokens</mark> response |

**Example:**[**​**](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#example)

```
Request: POST /mint
headers: {
  "IMX-Signature": "5257a869e7ecebeda32affa62cdca3fa51cad7e77a0e56ff536d0ce8e108d8bd",
  "IMX-Timestamp": "1492774577"
}

data: {
  "offer_id": "string",
  "contract_address": "string",
  "user": "string",
  "wallet_address": "string",
  "external_transaction_id": "string(UUID)",
}

Status: 200
Response: {
  "contract_address": "string",
  "token_id": "string",
  "tx_id": 0
}
```

ERROR ON MINT

If minting fails, please provide a response with the error code and message.

```
Response: {
 "code": "number", // the error code
 "message": "string", // the error message
 "details": "string" // the error details
}
```

#### Get asset info endpoint[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#get-asset-info-endpoint) <a href="#get-asset-info-endpoint" id="get-asset-info-endpoint"></a>

This endpoint will be used to get information about the asset to be minted using <mark style="color:blue;">trigger mint endpoint</mark>.

**Response:**[**​**](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#response-1)

| Property              | Type   | Description                                                                                |
| --------------------- | ------ | ------------------------------------------------------------------------------------------ |
| `offer_id`            | String | The ID of the offer provided for the NFT to be minted                                      |
| `contract_address`    | String | Smart contract address of the NFT                                                          |
| `name`                | String | Token name to be rendered at checkout                                                      |
| `collection`          | String | Collection name to be rendered at checkout                                                 |
| `image_url`           | String | URL where the image to be displayed for the minted asset is hosted                         |
| `price_currency_code` | String | Currency of the amount to be paid. Choose from: `"ETH"` or `"USDC"`                        |
| `price`               | String | Amount of the currency required to mint the token                                          |
| `seller_address`      | String | Wallet address that will receive the payment, in crypto (from MoonPay), for the minted NFT |

**Example:**[**​**](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#example-1)

```
Example Request: GET /:contract_address/:offer_id

Status: 200
Response: {
 "offer_id": "123",
 "contract_address": "0xacb3...",
 "name": "SiShinylver Card Pack",
 "collection": "Gods Unchained",
 "image_url": "https://images.godsunchained.com/cardpack-images--marketing/256/mortal--neutral--shiny--legendary.png",
 "price": "125.29",
 "price_currency_code": "USD",
 "seller_address": "0xacb3...",
}
```

UNAVAILABLE OFFER

If an offer is unavailable, a response should return `404 - Not Found`.

```
Status: 404
Response: {
 "code": "404", // the error code
 "message": "Missing offer", // the error message
 "details": "The offer id {offer_id} is not a valid offer for purchase" // the error details
}
```

#### 2. Register with XpansionChain using created endpoints[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#2-register-with-immutable-x-using-created-endpoints) <a href="#id-2-register-with-immutable-x-using-created-endpoints" id="id-2-register-with-immutable-x-using-created-endpoints"></a>

When you've set up the endpoints required in the previous step, please register with XpansionChain using the <mark style="color:blue;">registerNftPrimarySalesContract</mark> API endpoint.

After registration, XpansionChain will send you a webhook key that will be used to validate the signature when initiating mint requests.

#### 3. How to validate the `IMX-Signature`[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#3-how-to-validate-the-imx-signature) <a href="#id-3-how-to-validate-the-imx-signature" id="id-3-how-to-validate-the-imx-signature"></a>

Generate a `signed_payload` by concatenating the following:

* `IMX-Timestamp` header
* The character `.`
* JSON payload of the message to be signed

Example:

```
const payload = JSON.stringify({
  offer_id: '1',
  contract_address: '0x23a...',
  user: '0x8b1...',
  wallet_address: '0x11a...',
  external_transaction_id: '00000000-0000-0000-aaaa-0000a000aa00',
});

const signed_payload = imx_timestamp_header_value + '.' + payload;
```

You will then need to compute an HMAC with the SHA-256 hash function using the webhook key that we provided when you <mark style="color:blue;">registered the endpoints with</mark> XpansionChain for the `signed_payload` and use it to compare the signature in the header:

```
import crypto from 'crypto-js';

const generatedSignature = crypto
  .HmacSHA256(signed_payload, webhookKey)
  .toString();
```

### More information[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#more-information) <a href="#more-information" id="more-information"></a>

#### Main flow diagram:[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#main-flow-diagram) <a href="#main-flow-diagram" id="main-flow-diagram"></a>

![NFT Checkout Primary Main flow](/files/uYogjx0klU8lQsxhF3Or)

#### Technical flow diagram:[​](https://docs.x.immutable.com/docs/x/setup-primary-sale-card-checkout#technical-flow-diagram) <a href="#technical-flow-diagram" id="technical-flow-diagram"></a>

![NFT Checkout Primary By Fiat Technical flow](/files/aF6kBCNiFdMjvtgSG5xs)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://xpansionchain-1.gitbook.io/xpansionchain/advanced-guides/nft-primary-sale-card-checkout/set-up-required-endpoints.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.