# API Only (Server to Server) > For the complete documentation index, see [llms.txt](/llms.txt). With API Only, platforms/merchants can access the Unipaas Pay-in functionalities to enable single payments, create tokens, create 3DS payments, recurring payments, and more. All these calls require the caller to have a secret key (Private\_Key). You can find instructions on how to get the private key [here](/docs/getting-started/). Use this API to build your own payment form and have complete control over your checkout page's look and feel. Caution In the API Only implementation you **collect and pass raw card data**.\ This requires you to assess your PCI compliance according to SAQ D, the most extensive form of self-certification. ## Before you begin Please note: If you send a transaction without any vendor ID - the transaction will be entered to the platform e-wallet and will be listed as a platform transaction ## Create a simple payment To create a simple payment you need the card and the shopper's information (email and country). After the shopper submits their payment details on your checkout page, you need to make a payment request to Unipaas. From your server make an **POST /pay-ins** request specifying: | Parameter name | Required | Description | Type | | ------------------ | -------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------ | | `amount` | Yes | The value of the payment | Number | | `currency` | Yes | The currency of the payment | String | | `orderId` | Yes | Your unique reference for this payment | String | | `paymentOption` | Yes | Buyer's payment option details (Object) | Object | | `consumer.email` | Yes | Buyer's email address | String | | `consumer.country` | Yes | Buyer's country code, ISO 2 letters | String | | `transactionType` | No | Values: `Auth` or `Sale`. The default is `Sale`. Use `Auth` in cases where you want to separate between the Authorization step and capture (read more [here](/docs/main-entities/)) | String | * cURL ```curl curl --location --request POST 'https://sandbox.unipaas.com/platform/pay-ins' \ --header 'Content-Type: application/json' \ --header 'Authorization: Bearer --YOUR_PRIVATE_KEY--' \ --data-raw '{ "amount": 50, "currency": "EUR", "platformOrderId": "13323", "paymentOption": { "paymentOptionType": "Card", "cardAccount": { "nameOnCard": "test shopper", "expYear": "23", "expMonth": "10", "number": "4000023104662535", "securityCode": "132", "externalMpi": { "eci": "2", "cavv": "ejJRWG9SWWRpU2I1M21DelozSXU=" } } }, "consumer": { "email": "david@unipaas.com", "country": "GB" }, "metadata": { "CustomerID": "457349" } }' ``` The following example shows the **POST /pay-ins** response: * JSON ```json { "status": "Approved", "authorizationId": "608682347e445aaa7ccd7a61", "authorizationStatus": "Captured", "transactionId": "608682347e445aaa7ccd7a64", "paymentOption": { "paymentOptionId": "608682367e445aaa7ccd7a65", "bin": "400002", "brand": "VISA", "last4digits": "2535", "cardType": "Credit", "expMonth": "10", "expYear": "23" }, "sellerIdentity": "6076ebff0f11f7d98514c4da", "currency": "EUR", "transactionAmount": 50, "declineCode": "0", "threeD": { "result": "", "challengePreferenceReason": "12", "whiteListStatus": "", "threeDreasonId": "", "eci": "2", "xid": "" }, "processor": { "processorAuthCode": "111216", "processorTransactionId": "1110000000013512555", "processorErrorCode": 0 }, "items": [], "orderId": "13323", "metadata": { "CustomerID": "457349" } } ``` | Parameter name | Description | | --------------------- | ----------------------------------------------------------------------------------------------------- | | `authorizationStatus` | The status of the Authorization. [Learn more](/docs/main-entities/) about Authorization Object | | `authorizationId` | The Authorization ID | | `transactionId` | The Transaction ID | | `paymentOption` | Payment option Object (which contain mask card data) | | `sellerIdentity` | The Vendor ID | | `orderId` | Your Reference ID | | `amount` | The amount of the payment | | `currency` | The currency of the payment | | `processor` | The processor Object. This Object contains the information from the acquirer for the specific payment | ## Store credit card details You can use this functionality when you want to store the shopper's card details for future use or as part of a Recurring Payment flow. Card schemes often insist on sending a zero-authorization transaction (amount=0) before allowing card credentials to be stored for future use. In Europe the card schemes require the completion of Strong Authentication Validation (3D SECURE 2) for each zero-authorization request. As 3D secure flow implementation involves both client, and server side, we thoroughly recommend you to use our Web SDK Store Card flow [Store Card](/docs/store-card-tokenization/) instead of implementing it on your own. If you still want to use the API Only flow, you should follow the 3D Secure guide with the following changes in the request: | Field | Value | Type | | ----------------- | ----- | ------ | | `amount` | 0 | Number | | `currency` | EUR | String | | `transactionType` | Auth | String | The response includes the **PaymentOptionId** field - this is the token of the card and you should keep it for future use. ## Create a simple payment with token As described in the previous section, the `paymentOptionId` is the token of the card. You should send it instead of the paymentOption object. | Parameter name | Required | Description | Type | | ------------------ | -------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------ | | `amount` | Yes | The value of the payment | Number | | `currency` | Yes | The currency of the payment | String | | `orderId` | Yes | Your unique reference for this payment | String | | `paymentOptionId` | Yes | The token of the card | String | | `consumer.email` | Yes | The shopper email address | String | | `consumer.country` | Yes | The shopper's country code. ISO 2 letters | String | | `transactionType` | No | Values: `Auth` or `Sale`. The default is `Sale`. Use `Auth` in cases where you want to separate between the Authorization step and capture (read more [here](/docs/main-entities/)) | String | ## Accept card-present payments To take in-person, card-present payments through a Unipaas POS terminal, see [Terminal Payments](/docs/terminal-payments/).